技术领域technical field
本公开涉及复合材料制备技术领域，具体地，涉及一种碳-碳复合材料及其制备方法。The present disclosure relates to the technical field of composite material preparation, in particular, to a carbon-carbon composite material and a preparation method thereof.
背景技术Background technique
碳/碳复合材料通常由碳纤维预制体通过化学气相渗透或浸渍工艺致密化而得到，其工艺步骤为预制体成型→多周期增密→高温石墨化→机加成型→涂层→包装。Carbon/carbon composites are usually obtained by densifying carbon fiber preforms through chemical vapor infiltration or impregnation processes. The process steps are preform molding→multi-cycle densification→high-temperature graphitization→machining→coating→packaging.
增密工艺主要是通过化学气相渗透工艺对预制体进行气体沉积，增密工艺一般需要经过以下步骤：反应气体通过层流向沉积衬底的过界层扩散；沉积衬底表面吸附反应气体，反应气体产生反应并形成固态产物和气体产物；产生的气体产物解吸附，并沿一边界层区域扩散；产生的气体产物排出。The densification process is mainly to deposit gas on the preform through the chemical vapor infiltration process. The densification process generally needs to go through the following steps: the reaction gas diffuses to the boundary layer of the deposition substrate through laminar flow; the reaction gas is adsorbed on the surface of the deposition substrate, and the reaction gas A reaction occurs and a solid product and a gaseous product are formed; the gaseous product generated desorbs and diffuses along a boundary layer region; the gaseous product generated is discharged.
由于反应气体需要扩散进入预制体内部后进行反应，而反应气体到达材料表面和芯部的难易程度不同，因此容易产生表面密度高、芯部密度低，造成预制体表面与芯部的密度差过大的现象；且随着反应的进行，材料表面增密后封锁了反应气体向芯部扩散的路径，使其更加难以扩散进入芯部沉积，导致密度梯度进一步增加，后续增密效果越来越差，形成恶性循环。由于增密效率低，因此通常需要进行多个周期沉积才能得到密度达到目标值的产品，从而又形成生产周期过长，生产效率过低的现象。Since the reaction gas needs to diffuse into the preform to react, and the difficulty of the reaction gas reaching the surface and core of the material is different, it is easy to produce high surface density and low core density, resulting in a density difference between the surface and core of the preform. and as the reaction proceeds, the surface of the material is densified and the path of the reaction gas to diffuse to the core is blocked, making it more difficult to diffuse into the core deposition, resulting in a further increase in the density gradient and subsequent densification. Worse, forming a vicious circle. Due to the low densification efficiency, multiple cycles of deposition are usually required to obtain a product with a density reaching the target value, resulting in a phenomenon that the production cycle is too long and the production efficiency is too low.
涂层工艺目的为封堵碳/碳复合材料表面的孔隙，降低其表面孔隙率。由于其主要作用于材料表面，因此涂层工艺和沉积工艺不同。在实际生产中，涂层的大部分时间为拆装炉所耗，涂层工艺时间短、涂层效果差，因此涂层工艺的性价比低。The purpose of the coating process is to block the pores on the surface of the carbon/carbon composite material and reduce its surface porosity. Because it mainly acts on the surface of the material, the coating process is different from the deposition process. In actual production, most of the coating time is consumed by disassembling and assembling the furnace, the coating process time is short, and the coating effect is poor, so the cost performance of the coating process is low.
发明内容Contents of the invention
本公开的目的是提供一种碳-碳复合材料及其制备方法，不仅可以避免沉积一段时间后产品表面封孔而导致后续增密困难以及容易导致产品表面和芯部密度差异大的问题，而且可以缩短整个预制体的制备周期，提高生产效率。The purpose of the present disclosure is to provide a carbon-carbon composite material and its preparation method, which can not only avoid the problems of subsequent densification difficulties caused by sealing pores on the surface of the product after a period of deposition, and easily lead to large differences in density between the surface and core of the product, but also The preparation period of the whole prefabricated body can be shortened and the production efficiency can be improved.
为了实现上述目的，本公开第一方面提供一种碳-碳复合材料，所述碳-碳复合材料任意两处位置的密度差为0.5g/cm3以下。In order to achieve the above object, the first aspect of the present disclosure provides a carbon-carbon composite material, wherein the density difference between any two positions of the carbon-carbon composite material is 0.5 g/cm3 or less.
可选地，将所述碳-碳复合材料的任意两处位置的密度差记为M、厚度记为H，所述M与H具有以下特征：当0mm＜H≤30mm，所述M为0.05g/cm3以下；当30mm＜H≤60mm，所述M为0.15g/cm3以下；当60mm＜H≤100mm，所述M为0.5g/cm3以下。Optionally, the density difference between any two positions of the carbon-carbon composite material is denoted as M, and the thickness is denoted as H, and the M and H have the following characteristics: when 0mm<H≤30mm, the M is 0.05 g/cm3 or less; when 30mm<H≤60mm, the M is 0.15g/cm3 or less; when 60mm<H≤100mm, the M is 0.5g/cm3 or less.
可选地，所述碳-碳复合材料的包括含碳基体和覆于所述含碳基体表面的碳涂层；所述含碳基体包括含碳纤维预制体以及位于所述含碳纤维预制体空隙中的沉积碳；可选地，所述含碳纤维预制体由碳纤维或者碳化硅纤维通过针刺、编织工艺制备得到；优选地，所述碳-碳复合材料的密度为1.1～1.9g/cm3，所述碳-碳复合材料的纤维含量为19～57重量％；可选地，所述碳-碳复合材料的形状包括块状、片状、回转体状和异型状。Optionally, the carbon-carbon composite material includes a carbon-containing matrix and a carbon coating covering the surface of the carbon-containing matrix; the carbon-containing matrix includes a carbon fiber preform and is located in the void of the carbon fiber preform carbon deposits; optionally, the carbon fiber preform is prepared from carbon fibers or silicon carbide fibers through needle punching and weaving processes; preferably, the carbon-carbon composite material has a density of 1.1-1.9 g/cm3 , The fiber content of the carbon-carbon composite material is 19-57% by weight; optionally, the shape of the carbon-carbon composite material includes a block shape, a sheet shape, a rotary body shape and a special shape.
本公开第二方面提供一种制备第一方面所述的碳-碳复合材料的方法，该方法包括以下步骤：S1、对含碳预制体进行化学气相渗透处理，得到第一产物；S2、对所述第一产物进行成型处理，得到第二产物；S3、对所述第二产物进行化学气相反应处理，得到第三产物。The second aspect of the present disclosure provides a method for preparing the carbon-carbon composite material described in the first aspect, the method comprising the following steps: S1, performing chemical vapor infiltration treatment on a carbon-containing preform to obtain a first product; S2, performing a chemical vapor infiltration treatment on a carbon-containing preform; The first product is subjected to molding treatment to obtain a second product; S3, the second product is subjected to chemical gas phase reaction treatment to obtain a third product.
可选地，步骤S1中，所述含碳预制体包括碳纤维预制体和碳化硅预制体中的一种或两种；可选地，所述含碳预制体为碳纤维预制体，所述含碳预制体的密度为0.1～0.8g/cm3；所述含碳预制体为碳化硅预制体，所述含碳预制体的密度为0.3～1.0g/cm3；优选地，所述含碳预制体为碳纤维预制体；可选地，所述含碳预制体的形状包括块状、片状、回转体状和异型状，优选地，所述含碳预制体的厚度为5～100mm。Optionally, in step S1, the carbon-containing preform includes one or both of a carbon fiber preform and a silicon carbide preform; optionally, the carbon-containing preform is a carbon fiber preform, and the carbon-containing preform The density of the preform is 0.1-0.8 g/cm3 ; the carbon-containing preform is a silicon carbide preform, and the density of the carbon-containing preform is 0.3-1.0 g/cm3 ; preferably, the carbon-containing preform The body is a carbon fiber preform; optionally, the shape of the carbon-containing preform includes a block shape, a sheet shape, a revolution shape and a special shape, and preferably, the thickness of the carbon-containing preform body is 5-100 mm.
可选地，步骤S1中，所述化学气相渗透处理的工艺条件包括：反应气流量为500～1500L/min，炉内气体压强为12kPa以下，温度为930～1150℃，处理时间为50～500h，所述含碳预制体的处理量为800～2500kg；优选地，反应气流量为700～1200L/min，炉内气体压强为3.5～7.0kPa，温度为1050～1110℃，处理时间为150～200h，所述含碳预制体的处理量为1300～2000kg；其中所述化学气相渗透处理使用的反应气包括烃类气体；优选为选自天然气、乙烷、乙烯、丙烷和丙烯中的一种或几种。Optionally, in step S1, the process conditions of the chemical vapor infiltration treatment include: the reaction gas flow rate is 500-1500L/min, the gas pressure in the furnace is below 12kPa, the temperature is 930-1150°C, and the treatment time is 50-500h , the processing capacity of the carbon-containing preform is 800-2500kg; preferably, the reaction gas flow rate is 700-1200L/min, the gas pressure in the furnace is 3.5-7.0kPa, the temperature is 1050-1110°C, and the processing time is 150- 200h, the processing capacity of the carbon-containing preform is 1300-2000kg; wherein the reaction gas used in the chemical vapor infiltration treatment includes hydrocarbon gas; preferably selected from natural gas, ethane, ethylene, propane and propylene or several.
可选地，步骤S1中，所述含碳预制体为碳纤维预制体，所述第一产物的密度为1.0～1.5g/cm3；或者所述含碳预制体为碳化硅预制体，所述第一产物的密度为1.1～1.6g/cm3。Optionally, in step S1, the carbon-containing preform is a carbon fiber preform, and the density of the first product is 1.0-1.5 g/cm3 ; or the carbon-containing preform is a silicon carbide preform, and the The density of the first product is 1.1-1.6 g/cm3 .
可选地，步骤S2中，所述成型处理包括将所述第一产物进行切割处理、机加处理和打磨处理，得到所述第二产物；优选地，所述含碳预制体为碳纤维预制体，所述第二产物的密度为0.8～1.4g/cm3；或者，所述含碳预制体为碳化硅预制体，所述第二产物的密度为0.9～1.5g/cm3。Optionally, in step S2, the forming treatment includes cutting, machining and grinding the first product to obtain the second product; preferably, the carbon-containing preform is a carbon fiber preform , the density of the second product is 0.8-1.4 g/cm3 ; or, the carbon-containing preform is a silicon carbide preform, and the density of the second product is 0.9-1.5 g/cm3 .
可选地，步骤S3中，所述化学气相反应处理的工艺条件包括：反应气流量为250～1500L/min，炉内气体压强为12kPa以下，温度为930～1150℃，处理时间为20～300h；其中所述化学气相反应处理使用的反应气为烃类气体，优选为天然气、乙烷、乙烯、丙烷和丙烯中的一种或几种；可选地，所述工艺条件包括稀释气体，所述稀释气体选自氮气、氩气和氢气中的一种或几种，所述稀释气体流量为0～750L/min。Optionally, in step S3, the process conditions of the chemical vapor phase reaction treatment include: the reaction gas flow rate is 250-1500 L/min, the gas pressure in the furnace is below 12kPa, the temperature is 930-1150°C, and the treatment time is 20-300h ; wherein the reaction gas used in the chemical gas phase reaction treatment is hydrocarbon gas, preferably one or more of natural gas, ethane, ethylene, propane and propylene; optionally, the process conditions include diluent gas, so The dilution gas is selected from one or more of nitrogen, argon and hydrogen, and the flow rate of the dilution gas is 0-750L/min.
可选地，步骤S3中，所述化学气相沉积包括n段处理，n为1以上的整数；优选地，所述n为2～30之间的任意整数。Optionally, in step S3, the chemical vapor deposition includes n stages of processing, where n is an integer greater than 1; preferably, the n is any integer between 2 and 30.
可选地，所述第n段化学气相反应处理的反应气流量小于前n-1段化学气相反应处理中任意一段的反应气流量；所述第n段化学气相反应处理的压强小于前n-1段化学气相反应处理中任意一段的压强。Optionally, the reaction gas flow rate of the nth chemical gas phase reaction treatment is less than the reaction gas flow rate of any period in the first n-1 chemical gas phase reaction treatment; the pressure of the nth chemical gas phase reaction treatment is less than the previous n-1 The pressure of any stage in the 1st stage chemical gas phase reaction treatment.
可选地，步骤S3中，当n＝2时，第一段化学气相反应处理为化学气相渗透增密处理，其工艺条件包括：反应气流量Qf1为250～1500L/min，炉内气体压强P1为12kPa以下，温度T1为930～1150℃，处理时间t1为20～300h；Optionally, in step S3, when n=2, the first stage of chemical vapor reaction treatment is chemical vapor infiltration densification treatment, and its process conditions include: the reaction gas flow rate Qf1 is 250-1500 L/min, the gas pressure in the furnace isP1 is below 12kPa, temperatureT1 is 930~1150℃, and treatment timet1 is 20~300h;
第二段化学气相反应处理为化学气相沉积封孔涂层处理，其工艺条件包括：反应气流量Qf2为150～1400L/min，炉内气体压强P2为12kPa以下，温度T2为930℃～1150℃，处理时间t2为20～300h；优选地，Qf2＜Qf1，P2＜P1；The second chemical vapor phase reaction treatment is chemical vapor deposition sealing coating treatment, and its process conditions include: reaction gas flow Qf2 is 150-1400L/min, gas pressureP2 in the furnace is below 12kPa, and temperatureT2 is 930°C ~1150°C, the treatment timet2 is 20~300h; preferably, Qf2 <Qf1 , P2 <P1 ;
当n＞2时，第i段化学气相反应处理为化学气相渗透增密处理，其工艺条件包括：反应气流量Qfi为250～1500L/mini炉内气体压强为12kPa以下，Ti温度为930～1150℃，ti处理时间为20～300h，优选为20～50h；其中i选自1至n-1中的任意整数，且Qfi+1＜Qfi，Pi+1＜Pi；When n>2, the i-th chemical vapor phase reaction treatment is chemical vapor phase infiltration densification treatment, and its process conditions include: the reaction gas flow rate Qfi is 250-1500L/min, the gas pressure inthe i furnace is below 12kPa, and the Ti temperature is 930～1150℃, ti treatment time is 20～300h, preferably 20～50h; wherein i is selected from any integer from 1 to n-1, and Qfi+1 <Qfi , Pi+1 <Pi ;
第n段化学气相反应处理为化学气相沉积封孔涂层处理，工艺条件包括：反应气流量Qfn为150～1400L/min，Pn炉内气体压强为12kPa以下，Tn温度为930℃～1150℃，tn处理时间为20～300h，优选为20～50h；The chemical vapor phase reaction treatment in the nth stage is chemical vapor deposition sealing coating treatment. The process conditions include: the reaction gas flow Qfn is 150-1400L/min, the gas pressure in the Pn furnace is below 12kPa, and the Tn temperature is 930 ° C ~ 1150°C, tn treatment time is 20-300h, preferably 20-50h;
优选地，所述工艺条件还包括稀释气体，所述稀释气体选自氮气、氩气和氢气中的一种或几种；Preferably, the process conditions also include a diluent gas, and the diluent gas is selected from one or more of nitrogen, argon and hydrogen;
其中，当n＝2时，以稀释气体和反应气体的总流量计，第二段化学气相反应处理的工艺条件中稀释气体流量的流量占比大于第一段化学气相反应处理的工艺条件中稀释气体流量占比；Wherein, when n=2, based on the total flow rate of the dilution gas and the reaction gas, the flow ratio of the dilution gas flow rate in the process conditions of the second stage of chemical gas phase reaction treatment is greater than that of the dilution gas flow rate in the process conditions of the first stage of chemical vapor phase reaction treatment. gas flow ratio;
优选地，第一段化学气相反应处理的工艺条件中稀释气体：反应气的流量比为(0～0.3)：1；第二段化学气相反应处理的工艺条件中稀释气体：反应气的流量比为(0.3～0.5)：1；Preferably, the diluent gas: reaction gas flow ratio in the process conditions of the first stage of chemical vapor reaction treatment is (0-0.3): 1; the diluent gas: reaction gas flow ratio in the process conditions of the second stage chemical vapor reaction treatment For (0.3～0.5): 1;
其中，当n＞2时，所述第n段化学气相反应处理的工艺条件中稀释气体的流量占比大于第i段化学气相反应处理的工艺条件中稀释气体流量的流量占比；Wherein, when n>2, the flow ratio of the diluent gas in the process conditions of the nth stage of chemical gas phase reaction treatment is greater than the flow rate of the diluent gas flow in the process conditions of the i stage of chemical gas phase reaction treatment;
优选地，第i段化学气相反应处理的工艺条件中稀释气体：反应气的流量比为(0～0.3)：1；第n段化学气相反应处理的工艺条件中稀释气体：反应气的流量比为(0.3～0.5)：1。Preferably, the flow ratio of diluent gas: reaction gas in the process conditions of the i-th stage chemical gas phase reaction treatment is (0-0.3): 1; For (0.3～0.5):1.
可选地，步骤S3中，第i段化学气相反应处理和第i+1段化学气相反应处理的工艺条件具有以下特征：Optionally, in step S3, the process conditions of the i-th chemical gas phase reaction treatment and the i+1th chemical gas phase reaction treatment have the following characteristics:
0＜Qfi-Qfi+1≤500L/min；优选地，反应气流量降低速率为1～20(L/min)/h；以及0<Qfi -Qfi+1 ≤500L/min; preferably, the reaction gas flow rate decreases at a rate of 1 to 20 (L/min)/h; and
0＜Pi-Pi+1≤3kPa；优选地，压强降低速率为1kPa/h以下；0<Pi -Pi+1 ≤3kPa; preferably, the pressure decrease rate is below 1kPa/h;
进一步优选地，在第一段至第n-1段的化学气相渗透增密处理中，每段处理时间各自独立地为10～110h；Further preferably, in the chemical vapor infiltration densification treatment from the first stage to the n-1 stage, the treatment time of each stage is independently 10 to 110 hours;
进一步优选地，步骤S3中，第一段至第n段处理的总时间为20～150h。Further preferably, in step S3, the total time for processing from the first stage to the nth stage is 20-150 hours.
可选地，所述第一段或第i段化学气相渗透增密处理所得产物的密度为1.0～1.8g/cm3；优选地，所得产物密度为1.1～1.4g/cm3；所述第二段或第n段化学气相沉积封孔涂层处理所得产物的密度为1.2～1.9g/cm3；优选地，密度为1.35～1.7g/cm3。Optionally, the density of the product obtained in the first stage or the i-stage chemical vapor infiltration densification treatment is 1.0-1.8 g/cm3 ; preferably, the density of the obtained product is 1.1-1.4 g/cm3 ; The density of the product obtained from the second-stage or n-stage chemical vapor deposition sealing coating treatment is 1.2-1.9 g/cm3 ; preferably, the density is 1.35-1.7 g/cm3 .
可选地，该方法还包括：对步骤S3所得产物进行石墨化处理，所述石墨化处理的工艺条件包括：在惰性气氛下，石墨化温度为1600～2400℃，石墨化时间为2～6h；所述惰性气氛选自氮气和氩气中的一种或两种。Optionally, the method further includes: performing graphitization treatment on the product obtained in step S3, and the process conditions of the graphitization treatment include: under an inert atmosphere, the graphitization temperature is 1600-2400°C, and the graphitization time is 2-6h ; The inert atmosphere is selected from one or both of nitrogen and argon.
通过上述技术方案，本公开提供了一种碳-碳复合材料及其制备方法，所述碳-碳复合材料任意两处位置的密度差小，显著降低了复合材料表面以及芯部的密度差异；并且碳-碳复合材料产品质量好，表面无炭黑结壳现象。本公开在碳-碳复合材料制备过程中，对含碳预制体先进行第一化学气相渗透处理，在增密一段时间后通过成型处理可以达到打开材料表面孔隙的目的，提高后续增密效率；并且成型处理后产品厚度变薄，在后续沉积过程中有利于降低表面和芯部的密度差异；本公开在化学气相反应处理过程中，在一个工艺周内期即可实现增密和形成涂层，显著缩短了工艺时间，提高生产效率。Through the above technical solution, the present disclosure provides a carbon-carbon composite material and a preparation method thereof. The density difference between any two positions of the carbon-carbon composite material is small, which significantly reduces the density difference between the surface and the core of the composite material; Moreover, the carbon-carbon composite material product is of good quality, and there is no carbon black crusting phenomenon on the surface. In the present disclosure, during the preparation process of the carbon-carbon composite material, the first chemical vapor infiltration treatment is performed on the carbon-containing prefabricated body, and after a period of densification, the purpose of opening the surface pores of the material can be achieved through molding treatment to improve the subsequent densification efficiency; And the thickness of the product becomes thinner after the molding treatment, which is beneficial to reduce the density difference between the surface and the core in the subsequent deposition process; the present disclosure can achieve densification and coating formation within one process cycle during the chemical vapor phase reaction treatment process , Significantly shorten the process time and improve production efficiency.
本公开的其他特征和优点将在随后的具体实施方式部分予以详细说明。Other features and advantages of the present disclosure will be described in detail in the detailed description that follows.
附图说明Description of drawings
附图是用来提供对本公开的进一步理解，并且构成说明书的一部分，与下面的具体实施方式一起用于解释本公开，但并不构成对本公开的限制。在附图中：The accompanying drawings are used to provide a further understanding of the present disclosure, and constitute a part of the description, together with the following specific embodiments, are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the attached picture:
图1是本公开提供的制备碳-碳复合材料的方法的一种示例性工艺流程图。FIG. 1 is an exemplary process flow diagram of the method for preparing a carbon-carbon composite material provided by the present disclosure.
图2是实施例1所得产物的外观照片。Fig. 2 is the appearance photograph of the product obtained in embodiment 1.
图3是实施例1所得产物的外观照片。Fig. 3 is the appearance photograph of the product obtained in embodiment 1.
图4是实施例4所得产物的外观照片。Fig. 4 is the appearance photograph of the product obtained in embodiment 4.
图5a是实施例5所得产物的外观照片。Figure 5a is a photograph of the appearance of the product obtained in Example 5.
图5b是实施例5所得产物的外观照片。Figure 5b is a photo of the appearance of the product obtained in Example 5.
图6a是对比例1所得产物的外观照片。Figure 6a is a photograph of the appearance of the product obtained in Comparative Example 1.
图6b是对比例1所得产物的外观照片。Figure 6b is a photograph of the appearance of the product obtained in Comparative Example 1.
具体实施方式Detailed ways
以下结合附图对本公开的具体实施方式进行详细说明。应当理解的是，此处所描述的具体实施方式仅用于说明和解释本公开，并不用于限制本公开。Specific embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.
本公开第一方面提供一种碳-碳复合材料，所述任意两处位置的密度差为0.5g/cm3以下。The first aspect of the present disclosure provides a carbon-carbon composite material, wherein the density difference between any two positions is less than 0.5 g/cm3 .
本公开提供了一种碳-碳复合材料，所述碳-碳复合材料任意两处位置的密度差小，显著降低了复合材料表面以及芯部的密度差异；并且碳-碳复合材料产品质量好，表面无炭黑结壳现象。The present disclosure provides a carbon-carbon composite material, the density difference between any two positions of the carbon-carbon composite material is small, which significantly reduces the density difference between the surface and the core of the composite material; and the product quality of the carbon-carbon composite material is good , There is no carbon black crusting phenomenon on the surface.
本公开中“任意两处位置的密度差”是在复合材料任意两个位置处取标准体积的样品，按照质量/体积分别计算得到两个位置样品的平均密度，进而根据两个位置样品的平均密度计算得到密度差；该两个位置处的距离以两个位置样品的中心点之间距离为准；其中取样的标准体积为55mm×10mm×5mm。取样的标准体积也可以根据实际情况进行调整。The "density difference between any two positions" in this disclosure refers to taking standard volume samples at any two positions of the composite material, and calculating the average density of the samples at the two positions according to mass/volume, and then according to the average density of the samples at the two positions Calculate the density to get the density difference; the distance between the two positions is based on the distance between the center points of the samples at the two positions; the standard volume of sampling is 55mm×10mm×5mm. The standard volume of sampling can also be adjusted according to the actual situation.
在一种优选实施方式中，将所述碳-碳复合材料任意两处位置的密度差记为M、厚度记为H，所述M与H具有以下特征：In a preferred embodiment, the density difference between any two positions of the carbon-carbon composite material is denoted as M, and the thickness is denoted as H, and the M and H have the following characteristics:
当0mm＜H≤30mm，所述M为0.05g/cm3以下；When 0mm<H≤30mm, the M is below 0.05g/cm3 ;
当30mm＜H≤60mm，所述M为0.15g/cm3以下；When 30mm<H≤60mm, the M is below 0.15g/cm3 ;
当60mm＜H≤100mm，所述M为0.5g/cm3以下。When 60mm<H≤100mm, the M is below 0.5g/cm3 .
本公开中，以复合材料芯部的密度作为复合材料整体的密度最小值，以表面的密度作为复合材料整体的密度最大值，并将表面与芯部之间的密度差作为复合材料整体的最大密度差。In this disclosure, the density of the core of the composite material is taken as the minimum density of the composite material as a whole, the density of the surface is taken as the maximum density of the composite material as a whole, and the density difference between the surface and the core is taken as the maximum density of the composite material as a whole. poor density.
具体地，本公开中“厚度”与本领域技术人员常规理解和计量方式相同，厚度表示两个表面之间的垂直距离；例如当复合材料为规则形状时(如立方体、正方体等)，复合材料的整体厚度相对均匀，复合材料的表面上某处的厚度为任意一处两个表面的垂直距离；当复合材料为不规则形状时，复合材料的整体厚度不太均匀，“厚度”表示该复合材料的某一位置处的厚度，而并非是采用平均厚度、最大厚度等来表征复合材料的厚度，当在复合材料取某一位置处的厚度时，为该位置处的两个表面的垂直距离，其主要也是为了测量表面到芯部的距离，该处的厚度唯一且固定。Specifically, the "thickness" in the present disclosure is the same as the conventional understanding and measurement method of those skilled in the art, and the thickness means the vertical distance between two surfaces; for example, when the composite material is a regular shape (such as a cube, a cube, etc.), the composite material The overall thickness of the composite material is relatively uniform, and the thickness of a certain place on the surface of the composite material is the vertical distance between any two surfaces; when the composite material is irregular in shape, the overall thickness of the composite material is not uniform, and "thickness" indicates the composite The thickness at a certain position of the material, instead of using the average thickness, maximum thickness, etc. to characterize the thickness of the composite material, when the thickness at a certain position is taken in the composite material, it is the vertical distance between the two surfaces at this position , which is also mainly used to measure the distance from the surface to the core, where the thickness is unique and fixed.
一种实施方式中，所述碳-碳复合材料的包括含碳基体和覆于所述含碳基体表面的碳涂层；In one embodiment, the carbon-carbon composite material includes a carbon-containing substrate and a carbon coating covering the surface of the carbon-containing substrate;
所述含碳基体包括含碳纤维预制体以及位于所述含碳纤维预制体空隙中的沉积碳；The carbon-containing matrix includes a carbon fiber preform and deposited carbon located in the voids of the carbon fiber preform;
可选地，所述含碳纤维预制体由碳纤维或者碳化硅纤维通过针刺、编织工艺制备得到。Optionally, the carbon fiber-containing preform is prepared from carbon fibers or silicon carbide fibers through needle-punching and weaving processes.
一种具体实施方式中，所述碳-碳复合材料的密度为1.1～1.9g/cm3；所述碳-碳复合材料的纤维含量为19～57重量％。In a specific implementation manner, the density of the carbon-carbon composite material is 1.1-1.9 g/cm3 ; the fiber content of the carbon-carbon composite material is 19-57% by weight.
本公开中碳-碳复合材料的密度为碳-碳复合材料整体平均密度，按照材料整体的质量/体积计算得到。The density of the carbon-carbon composite material in the present disclosure is the overall average density of the carbon-carbon composite material, calculated according to the mass/volume of the entire material.
一种具体实施方式中，所述碳-碳复合材料的形状包括块状、片状、回转体状和异型状。本公开的碳-碳复合材料的具体形状可以根据实际产品需求进行加工处理得到。In a specific embodiment, the shape of the carbon-carbon composite material includes a block shape, a sheet shape, a revolution shape and a special shape. The specific shape of the carbon-carbon composite material of the present disclosure can be obtained by processing according to actual product requirements.
本公开第二方面提供一种制备第一方面所述的碳-碳复合材料的方法，该方法包括以下步骤：The second aspect of the present disclosure provides a method for preparing the carbon-carbon composite material described in the first aspect, the method comprising the following steps:
S1、对含碳预制体进行化学气相渗透处理，得到第一产物；S1. Carrying out chemical vapor infiltration treatment on the carbon-containing preform to obtain the first product;
S2、对所述第一产物进行成型处理，得到第二产物；S2. Perform molding treatment on the first product to obtain a second product;
S3、对所述第二产物进行化学气相反应处理，得到第三产物。S3. Performing chemical gas phase reaction treatment on the second product to obtain a third product.
本公开在碳-碳复合材料制备过程中，对含碳预制体先进行第一化学气相渗透处理，在增密一段时间后通过成型处理可以达到打开材料表面孔隙的目的，提高后续增密效率；并且成型处理后产品厚度变薄，在后续沉积过程中有利于降低表面和芯部的密度差异；本公开在化学气相反应处理过程中，在一个工艺周内期即可实现增密和形成涂层，显著缩短了工艺时间，提高生产效率。In the present disclosure, during the preparation process of the carbon-carbon composite material, the first chemical vapor infiltration treatment is performed on the carbon-containing prefabricated body, and after a period of densification, the purpose of opening the surface pores of the material can be achieved through molding treatment to improve the subsequent densification efficiency; And the thickness of the product becomes thinner after the molding treatment, which is beneficial to reduce the density difference between the surface and the core in the subsequent deposition process; the present disclosure can achieve densification and coating formation within one process cycle during the chemical vapor phase reaction treatment process , Significantly shorten the process time and improve production efficiency.
一种具体实施方式中，所述含碳预制体包括碳纤维预制体和碳化硅预制体中的一种或两种；In a specific embodiment, the carbon-containing preform includes one or both of a carbon fiber preform and a silicon carbide preform;
可选地，所述含碳预制体为碳纤维预制体，所述含碳预制体的密度为0.1～0.8g/cm3；Optionally, the carbon-containing preform is a carbon fiber preform, and the density of the carbon-containing preform is 0.1-0.8 g/cm3 ;
所述含碳预制体为碳化硅预制体，所述含碳预制体的密度为0.3～1.0g/cm3。本公开中含碳预制体的密度为整体平均密度，按照材料整体的质量/体积计算得到。The carbon-containing preform is a silicon carbide preform, and the density of the carbon-containing preform is 0.3-1.0 g/cm3 . The density of the carbon-containing preform in the present disclosure is the overall average density, calculated according to the mass/volume of the entire material.
一种优选实施方式中，所述含碳预制体为碳纤维预制体。In a preferred embodiment, the carbon-containing preform is a carbon fiber preform.
一种具体实施方式中，所述含碳预制体由碳纤维和碳化硅纤维中的一种或两种通过针刺或者编织工艺制备得到；也可以通过常规渠道购买得到，或者通过本领域已知的方法制备得到。In a specific embodiment, the carbon-containing preform is prepared from one or both of carbon fibers and silicon carbide fibers through needle-punching or weaving processes; it can also be purchased through conventional channels, or through known in the art method prepared.
一种实施方式中，所述含碳预制体的形状包括块状、片状、回转体状和异型状，优选地，所述含碳预制体的厚度为5～100mm。本公开采用的含碳预制体可以采用多种形状，并且预制体厚度可以在较大范围内变化。In one embodiment, the shape of the carbon-containing preform includes a block shape, a sheet shape, a revolution shape and a special shape. Preferably, the thickness of the carbon-containing preform body is 5-100 mm. The carbonaceous preforms employed in the present disclosure can take a variety of shapes, and the preform thickness can vary over a wide range.
一种实施方式中，步骤S1中，所述化学气相渗透处理的工艺条件包括：在等温CVI炉中进行，反应气流量为500～1500L/min，炉内气体压强为12kPa以下，温度为930～1150℃，处理时间为50～500h，所述含碳预制体的处理量为800～2500kg；其中所述化学气相渗透处理使用的反应气包括烃类气体；优选为选自天然气、乙烷、乙烯、丙烷和丙烯中的一种或几种。本公开通过化学气相渗透处理对含碳预制体进行于预增密处理形成胚体。In one embodiment, in step S1, the process conditions of the chemical vapor infiltration treatment include: carrying out in an isothermal CVI furnace, the reaction gas flow rate is 500-1500 L/min, the gas pressure in the furnace is below 12 kPa, and the temperature is 930-1000 L/min. 1150°C, the treatment time is 50-500h, and the treatment capacity of the carbon-containing preform is 800-2500kg; wherein the reaction gas used in the chemical vapor infiltration treatment includes hydrocarbon gas; preferably selected from natural gas, ethane, ethylene One or more of , propane and propylene. In the present disclosure, the carbon-containing preform is subjected to pre-densification treatment through chemical vapor infiltration treatment to form an embryo body.
一种优选实施方式中，反应气流量为700～1200L/min，炉内气体压强为3.5～7.0kPa，温度为1050～1110℃，处理时间为150～200h，所述含碳预制体的处理量为1300～2000kg。采用优选的化学气相渗透处理工艺条件有利于降低碳-碳复合材料的密度差。In a preferred embodiment, the reaction gas flow rate is 700-1200L/min, the gas pressure in the furnace is 3.5-7.0kPa, the temperature is 1050-1110°C, and the treatment time is 150-200h. The processing capacity of the carbon-containing preform It is 1300-2000kg. The optimal chemical vapor infiltration treatment process conditions are beneficial to reduce the density difference of the carbon-carbon composite material.
一种具体实施方式中，所述含碳预制体为碳纤维预制体，所述第一产物的密度为1.0～1.5g/cm3；或者所述含碳预制体为碳化硅预制体，所述第一产物的密度为1.1～1.6g/cm3。In a specific embodiment, the carbon-containing preform is a carbon fiber preform, and the density of the first product is 1.0-1.5 g/cm3 ; or the carbon-containing preform is a silicon carbide preform, and the first product One product has a density of 1.1-1.6 g/cm3 .
一种实施方式中，步骤S2中，所述成型处理包括将所述第一产物进行切割处理、机加处理和打磨处理，得到所述第二产物。本公开中成型处理包括本领域常规进行的操作，例如机加处理为本领域常规的按图纸对粗胚体进行机加形成胚体。也可以根据实际需求将多种工艺组合使用。In one embodiment, in step S2, the forming treatment includes cutting, machining and grinding the first product to obtain the second product. The forming treatment in the present disclosure includes operations conventionally performed in the field, for example, machining treatment is conventional in the field to machine the rough embryo body according to the drawing to form an embryo body. Various processes can also be used in combination according to actual needs.
一种实施方式中，所述含碳预制体为碳纤维预制体，所述第二产物的密度为0.8～1.4g/cm3；或者所述含碳预制体为碳化硅预制体，所述第二产物的密度为0.9～1.5g/cm3。本公开中对预增密的第一产物进行成型处理来获得目标形状，成型处理过程中可能会除去产品密度较高的部分，在打开第一产物表面孔隙以及降低厚度的同时，产品密度仅略有减小，不会对产品密度造成较大影响。In one embodiment, the carbon-containing preform is a carbon fiber preform, and the density of the second product is 0.8-1.4 g/cm3 ; or the carbon-containing preform is a silicon carbide preform, and the second The product has a density of 0.9-1.5 g/cm3 . In the present disclosure, the pre-densified first product is subjected to molding treatment to obtain the target shape. During the molding treatment, the part with higher density of the product may be removed. While opening the surface pores of the first product and reducing the thickness, the product density is only slightly If there is a reduction, it will not have a great impact on the product density.
一种实施方式中，步骤S3中，所述化学气相反应处理在等温CVI炉中进行，工艺条件包括：反应气流量为250～1500L/min，炉内气体压强为12kPa以下，温度为930～1150℃，处理时间为20～300h；其中所述化学气相反应处理使用的反应气为烃类气体，优选为天然气、乙烷、乙烯、丙烷和丙烯中的一种或几种。In one embodiment, in step S3, the chemical vapor phase reaction treatment is carried out in an isothermal CVI furnace, and the process conditions include: the reaction gas flow rate is 250-1500 L/min, the gas pressure in the furnace is below 12 kPa, and the temperature is 930-1150 °C, and the treatment time is 20-300 hours; wherein the reaction gas used in the chemical vapor phase reaction treatment is hydrocarbon gas, preferably one or more of natural gas, ethane, ethylene, propane and propylene.
本公开在化学气相反应处理中，实现了沉积增密和涂层在同一周期内完成，大大提高了涂层质量，降低了生产周期，提高了生产效率，并且也无需频繁拆装炉和产品降温升温等程序，进一步简化工艺、缩短时间。In the chemical gas phase reaction treatment, the present disclosure realizes deposition densification and coating in the same cycle, greatly improves the coating quality, reduces the production cycle, improves production efficiency, and does not require frequent disassembly and assembly of furnaces and product cooling Heating and other procedures further simplify the process and shorten the time.
根据本公开，步骤S3沉积过程中可以不引入稀释气体，简化工艺、节约资源；也可以引入稀释气体。一种优选实施方式中，所述工艺条件包括稀释气体，所述稀释气体选自氮气、氩气和氢气中的一种或几种，所述稀释气体流量为0～750L/min，优选为100～350L/min；可选地，稀释气体：反应气的流量比为(0～0.5)：1。According to the present disclosure, no diluent gas may be introduced during the deposition process in step S3, which simplifies the process and saves resources; diluent gas may also be introduced. In a preferred embodiment, the process conditions include a dilution gas, the dilution gas is selected from one or more of nitrogen, argon and hydrogen, and the flow rate of the dilution gas is 0-750L/min, preferably 100 ~350L/min; Optionally, the diluent gas:reaction gas flow ratio is (0~0.5):1.
一种优选实施方式中，步骤S3中，所述化学气相沉积处理在等温CVI炉中进行，包括n段处理，n为1以上的整数；进一步优选地，所述第n段化学气相反应处理的反应气流量小于前n-1段化学气相反应处理中任意一段的反应气流量；所述第n段化学气相反应处理的压强小于前n-1段化学气相反应处理中任意一段的压强。本公开对一个周期内的化学气相沉积处理进行逐步减小或者阶梯式减小反应气流量和压强，有利于避免产品表面出现炭黑结壳现象。In a preferred embodiment, in step S3, the chemical vapor deposition treatment is carried out in an isothermal CVI furnace, including n-stage treatment, where n is an integer greater than 1; further preferably, the chemical vapor phase reaction treatment of the n-stage The reaction gas flow rate is less than the reaction gas flow rate of any section of the first n-1 chemical gas phase reaction treatment; the pressure of the nth chemical gas phase reaction treatment is less than the pressure of any section of the first n-1 chemical gas phase reaction treatment. In the present disclosure, the chemical vapor deposition treatment within a period is gradually reduced or the reaction gas flow rate and pressure are reduced stepwise, which is beneficial to avoiding the phenomenon of carbon black crusting on the surface of the product.
根据本公开，步骤S3中，化学气相渗透增密处理和化学气相沉积封孔涂层处理在同一等温CVI炉中连续进行，减少拆炉装炉操作。According to the present disclosure, in step S3, the chemical vapor infiltration densification treatment and the chemical vapor deposition sealing coating treatment are continuously performed in the same isothermal CVI furnace, reducing the operation of dismantling and installing the furnace.
一种具体实施方式中，步骤S3中，当n＝2时，第一段化学气相反应处理为化学气相渗透增密处理，其工艺条件包括：反应气流量Qf1为250～1500L/min，炉内气体压强P1为12kPa以下，温度T1为930～1150℃，处理时间t1为20～300h；In a specific embodiment, in step S3, when n=2, the first stage of chemical vapor phase reaction treatment is chemical vapor phase infiltration densification treatment, and its process conditions include: reaction gas flow rate Qf1 is 250-1500 L/min, furnace The internal gas pressureP1 is below 12kPa, the temperatureT1 is 930-1150°C, and the treatment timet1 is 20-300h;
第二段化学气相反应处理为化学气相沉积封孔涂层处理，其工艺条件包括：反应气流量Qf2为150～1400L/min，炉内气体压强P2为12kPa以下，温度T2为930℃～1150℃，处理时间t2为20～300h；优选地，Qf2＜Qf1，P2＜P1。The second chemical vapor phase reaction treatment is chemical vapor deposition sealing coating treatment, and its process conditions include: reaction gas flow Qf2 is 150-1400L/min, gas pressureP2 in the furnace is below 12kPa, and temperatureT2 is 930°C ~1150°C, the treatment time t2 is 20~300h; preferably, Qf2 <Qf1 , P2 <P1 .
在上述步骤中，对于第一阶段化学气相反应(化学气相渗透增密处理)，由于前期经过机加工处理，此时第二产物的孔隙被打开且相对均匀，通过再次的渗透处理，反应气体能够更易进入材料芯部，减少第二产物表面与芯部的密度差，由此在渗透过程中，有效减少了第二产物的密度差。当经过第一阶段化学气相反应的增密反应后，此时通过减少气体压力和反应气体的流量，减少碳源气体渗入芯部，促进碳源气体在表面形成沉积碳，实现封孔涂层的效果。与现有技术不同，本公开在第一阶段化学处理后，不需要拆炉后进行机加并重新装炉，有效节省了生产时间；而且第二阶段(化学气相沉积封孔涂层处理)是第一阶段完成后连续进行封孔处理，此时材料处于高温之中，渗透反应仍在持续进行，而此时进行封孔沉积一部分可以稍微弥补第一阶段可能存在的密度差，另外也可以使得反应气体更均匀的沉积在表面上，实现封孔涂层的目的。In the above steps, for the first-stage chemical vapor reaction (chemical vapor infiltration densification treatment), due to the machining treatment in the early stage, the pores of the second product are opened and relatively uniform at this time, and the reaction gas can It is easier to enter the core of the material, reducing the density difference between the surface of the second product and the core, thereby effectively reducing the density difference of the second product during the infiltration process. After the densification reaction of the first stage of chemical gas phase reaction, at this time, by reducing the gas pressure and the flow rate of the reaction gas, the infiltration of carbon source gas into the core is reduced, and the carbon source gas is promoted to form deposited carbon on the surface, so as to realize the sealing coating. Effect. Different from the prior art, after the first stage of chemical treatment, the present disclosure does not need to dismantle the furnace for machining and reinstall the furnace, which effectively saves production time; and the second stage (chemical vapor deposition sealing coating treatment) is the first After the completion of the first stage, the sealing treatment is carried out continuously. At this time, the material is at a high temperature, and the osmosis reaction is still going on. At this time, part of the sealing deposition can slightly compensate for the density difference that may exist in the first stage, and it can also make the reaction The gas is more uniformly deposited on the surface to achieve the purpose of sealing coating.
一种实施方式中，在对第二产物进行化学气相反应处理过程中，可以加入稀释气体；优选地，当n＝2时，以稀释气体和反应气体的总流量计，第二段化学气相反应处理的工艺条件中稀释气体流量的流量占比大于第一段化学气相反应处理的工艺条件中稀释气体流量占比；其中，流量占比的定义是指：稀释气体的流量在反应气体和稀释气体总流量中的比值。一种具体实施方式中，，具体地，第一阶段(化学气相渗透增密处理)稀释气体与反应气的流量比为(0～0.3)：1；第二阶段(化学气相沉积封孔涂层处理)的稀释气体与反应气的流量比为(0.3～0.5)：1；其中由于第二阶段主要是为了实现封孔涂层的目的，因为降低碳源气体的压强和流量以及增加氮气(稀释气体)流量，提高稀释气体占比，可以缩短滞留时间、降低气相中的大分子碳含量，从而减少产品表面产生炭黑和结壳。In one embodiment, during the chemical vapor phase reaction treatment process of the second product, a diluent gas can be added; preferably, when n=2, based on the total flow rate of the diluent gas and the reaction gas, the second stage of the chemical vapor phase reaction The flow ratio of the dilution gas flow rate in the process conditions of the treatment is greater than the flow rate ratio of the dilution gas flow rate in the process conditions of the first stage of chemical gas phase reaction treatment; where the definition of the flow rate ratio refers to: the flow rate of the dilution gas is between the reaction gas and the dilution gas Ratio of total flow. In a specific embodiment, specifically, the flow ratio of the dilution gas to the reaction gas in the first stage (chemical vapor infiltration densification treatment) is (0-0.3): 1; in the second stage (chemical vapor deposition sealing coating The flow ratio of dilution gas to reaction gas (0.3-0.5): 1; the second stage is mainly to achieve the purpose of sealing coating, because reducing the pressure and flow of carbon source gas and increasing nitrogen (dilute Gas) flow rate, increasing the proportion of diluted gas can shorten the residence time and reduce the macromolecular carbon content in the gas phase, thereby reducing the generation of carbon black and crusts on the product surface.
另一种具体实施方式中，步骤S3中，当n＞2时，第i段化学气相反应处理为化学气相渗透增密处理，其工艺条件包括：反应气流量Qfi为250～1500L/mini炉内气体压强为12kPa以下，Ti温度为930～1150℃，ti处理时间为20～300h；其中i选自1至n-1中的任意整数，且Qfi+1＜Qfi，Pi+1＜Pi；In another specific embodiment, in step S3, when n>2, the chemical vapor phase reaction treatment in the i-th stage is a chemical vapor phase infiltration densification treatment, and its process conditions include: the reaction gas flow rate Qfi is 250-1500 L/mini The gas pressure in the furnace is below 12kPa, the Ti temperature is 930-1150°C, and the ti treatment time is 20-300h; where i is selected from any integer from 1 to n-1, and Qfi+1 < Qfi , Pi+1 <Pi ;
第n段化学气相反应处理为化学气相沉积封孔涂层处理，工艺条件包括：反应气流量Qfn为150～1400L/min，Pn炉内气体压强为12kPa以下，Tn温度为930℃～1150℃，tn处理时间为20～300h，优选为20～50h。The chemical vapor phase reaction treatment in the nth stage is chemical vapor deposition sealing coating treatment. The process conditions include: the reaction gas flow Qfn is 150-1400L/min, the gas pressure in the Pn furnace is below 12kPa, and the Tn temperature is 930 ° C ~ 1150°C, tn treatment time is 20-300h, preferably 20-50h.
本公开在同一等温CVI炉中进行多段化学气相反应处理也无需拆装炉，可以在一个周期内完成增密和涂层的条件下，进一步降低复合材料的密度差；并且在多段工艺中将增密和涂层的工艺区分开，有利于防止在涂层工艺中产生炭黑、结壳等现象，提高复合材料产品的美观性和产品质量。In the present disclosure, the multi-stage chemical gas phase reaction treatment in the same isothermal CVI furnace does not need to dismantle the furnace, and the density difference of the composite material can be further reduced under the condition of completing the densification and coating within one cycle; and the multi-stage process will increase The process of dense and coating is separated, which is beneficial to prevent the phenomenon of carbon black and crusting in the coating process, and improve the aesthetics and product quality of composite products.
一种实施方式中，步骤S3中，当n＞2时，以稀释气体和反应气体的总流量计，第n段化学气相反应处理的工艺条件中稀释气体的流量占比大于第i段化学气相反应处理的工艺条件中稀释气体流量的流量占比；In one embodiment, in step S3, when n>2, based on the total flow rate of the dilution gas and the reaction gas, the flow ratio of the dilution gas in the process conditions of the nth stage of chemical gas phase reaction treatment is greater than that of the ith stage of chemical vapor phase reaction treatment. The flow ratio of the dilution gas flow in the process conditions of the reaction treatment;
一种优选实施方式中，第i段化学气相反应处理的工艺条件中稀释气体：反应气的流量比为(0～0.3)：1；第n段化学气相反应处理的工艺条件中稀释气体：反应气的流量比为(0.3～0.5)：1。其中，在第二阶段(第n段处理)提高稀释气体占比，可以缩短滞留时间、降低气相中的大分子碳含量，从而减少产品表面产生炭黑和结壳。In a preferred embodiment, the diluent gas: reaction gas flow ratio in the process conditions of the i-th stage chemical gas phase reaction treatment is (0-0.3): 1; The gas flow ratio is (0.3-0.5):1. Among them, increasing the proportion of diluent gas in the second stage (n-stage treatment) can shorten the residence time and reduce the macromolecular carbon content in the gas phase, thereby reducing the generation of carbon black and crusts on the product surface.
在一种更优选的实施方式中，步骤S3中，第i段化学气相反应处理和第i+1段化学气相反应处理的工艺条件具有以下特征：In a more preferred embodiment, in step S3, the process conditions of the i-th section chemical vapor reaction treatment and the i+1 section chemical vapor reaction treatment have the following characteristics:
0＜Qfi-Qfi+1≤500L/min；0<Qfi -Qfi+1 ≤500L/min;
0＜Pi-Pi+1≤3kPa。0<Pi −Pi+1 ≤3kPa.
本公开在多段工艺中可以控制任意两段工艺的反应气流量和压强平缓或阶梯式减少，有利于进一步避免炭黑、结壳现象产生。In the present disclosure, in the multi-stage process, the reaction gas flow and pressure of any two-stage process can be controlled to decrease gently or stepwise, which is beneficial to further avoiding the occurrence of carbon black and crusting.
一种具体实施方式中，由第i段至第i+1段的化学气相反应处理工艺中，反应气流量降低速率为1～20(L/min)/h，压强降低速率为1kPa/h以下。In a specific embodiment, in the chemical gas phase reaction treatment process from the i-th section to the i+1-th section, the reaction gas flow rate decreases at a rate of 1 to 20 (L/min)/h, and the pressure decrease rate is below 1 kPa/h .
一种具体实施方式中，在第一段至第n-1段的化学气相渗透增密处理中，每段处理时间各自独立地为10～110h；进一步优选地，步骤S3中，第一段至第n段处理的总时间为30～150h。采用本公开提供的方法有利于进一步降低处理周期，提高处理效率。In a specific embodiment, in the chemical vapor infiltration densification treatment from the first stage to the n-1th stage, the treatment time of each stage is independently 10 to 110 hours; further preferably, in step S3, the first stage to The total time for the treatment of the nth stage is 30~150h. Adopting the method provided by the present disclosure is beneficial to further reduce the processing period and improve the processing efficiency.
一种具体实施方式中，步骤S3中，所述第一段或第i段化学气相渗透增密处理所得产物的密度为1.0～1.8g/cm3；优选地，所得产物密度为1.1～1.4g/cm3；所述第二段或第n段化学气相沉积封孔涂层处理所得产物的密度为1.2～1.9g/cm3；优选地，密度为1.35～1.7g/cm3。本公开中化学气相沉积封孔涂层处理前、后产物的密度也是按照整体质量/体积计算得到的平均密度。相比于化学气相渗透增密处理所得产物(封孔涂层处理前)，在化学气相沉积封孔涂层处理后可以显著降低产品表面的开孔度，降低产品的密度差。In a specific embodiment, in step S3, the density of the product obtained in the first stage or the i-stage chemical vapor infiltration densification treatment is 1.0-1.8 g/cm3 ; preferably, the density of the product obtained is 1.1-1.4 g /cm3 ; the density of the product obtained from the second or nth chemical vapor deposition sealing coating treatment is 1.2-1.9 g/cm3 ; preferably, the density is 1.35-1.7 g/cm3 . In the present disclosure, the density of the product before and after the chemical vapor deposition sealing coating is also the average density calculated according to the overall mass/volume. Compared with the product obtained by the chemical vapor infiltration densification treatment (before the sealing coating treatment), the opening of the product surface can be significantly reduced after the chemical vapor deposition sealing coating treatment, and the density difference of the product can be reduced.
一种实施方式中，该方法还包括：In one embodiment, the method also includes:
对步骤S3所得产物进行石墨化处理，所述石墨化处理的工艺条件包括：在惰性气氛下，石墨化温度为1600～2400℃，石墨化时间为2～6h；Carrying out graphitization treatment on the product obtained in step S3, the process conditions of the graphitization treatment include: under an inert atmosphere, the graphitization temperature is 1600-2400° C., and the graphitization time is 2-6 hours;
所述惰性气氛选自氮气和氩气中的一种或两种。本公开通过高温石墨化处理具有石墨化和纯化的双重效果，提高复合材料产品的稳定性。The inert atmosphere is selected from one or both of nitrogen and argon. The disclosure has dual effects of graphitization and purification through high-temperature graphitization treatment, and improves the stability of composite material products.
一种具体实施方式中，该方法还包括：检查产品外观、密度、涂层是否合格，若合格则包装入库，否则返工处理。In a specific embodiment, the method further includes: checking whether the appearance, density, and coating of the product are qualified, and if qualified, packaging and storing; otherwise, reprocessing.
一种具体实施方式中，如图1所示，制备碳-碳复合材料的方法依次包括：预制体制备、预制体增密(得到第一产物)、机加处理(得到第二产物)、沉积/封孔一体化处理(得到第三产物)、高温处理(石墨化处理)和包装入库，其中各步骤的具体操作和工艺参数在前述内容已经作了详细描述，在此不再赘述。In a specific embodiment, as shown in Figure 1, the method for preparing a carbon-carbon composite material sequentially includes: preform preparation, preform densification (obtaining the first product), machining treatment (obtaining the second product), deposition Hole sealing integrated treatment (to obtain the third product), high temperature treatment (graphitization treatment) and packaging storage, wherein the specific operation and process parameters of each step have been described in detail in the foregoing content, and will not be repeated here.
下面将结合实施例对本公开的技术方案做进一步说明。The technical solutions of the present disclosure will be further described below in conjunction with embodiments.
在以下实施例和对比例中复合材料整体密度按照材料整体的质量/体积计算得到；“任意两处位置的密度差”是在复合材料任意两个位置处取标准体积的样品，按照质量/体积分别计算得到两个位置处的样品的平均密度，进而根据两个位置处的样品的平均密度计算得到密度差；该两个位置处的距离以两个位置的样品的中心点之间距离为准；其中取样的标准体积为55mm×10mm×5mm。In the following examples and comparative examples, the overall density of the composite material is calculated according to the mass/volume of the material as a whole; "the density difference between any two positions" is to take samples of standard volumes at any two positions of the composite material, according to the mass/volume Calculate the average density of the samples at the two positions respectively, and then calculate the density difference according to the average density of the samples at the two positions; the distance between the two positions is based on the distance between the center points of the samples at the two positions ; The standard volume of sampling is 55mm×10mm×5mm.
在以下实施例中，采用的含碳预制体为碳纤维预制体，通过针刺成型工艺制备得到，所得多个碳纤维预制体的平均密度为0.42～0.45g/cm3范围内。其中单个含碳预制体的密度为整体平均密度，按照材料整体的质量/体积计算得到。In the following examples, the carbon-containing preforms used are carbon fiber preforms, which are prepared by needle punching, and the average density of the obtained carbon fiber preforms is in the range of 0.42-0.45 g/cm3 . The density of a single carbon-containing preform is the overall average density, calculated according to the mass/volume of the material as a whole.
在以下实施例和对比例中，含碳预制体的处理量为850～950kg。In the following examples and comparative examples, the treatment capacity of the carbon-containing preform is 850-950 kg.
在以下实施例和对比例中，制备所得碳-碳复合材料产品的纤维含量的通过称重法，分别称量预制体、第一产物、第二产物和成品的重量，然后通过下式(1)计算成品的纤维含量(即碳-碳复合材料产品的纤维含量)。In the following examples and comparative examples, the fiber content of the resulting carbon-carbon composite product is prepared by weighing, respectively weighing the weight of the preform, the first product, the second product and the finished product, and then by the following formula (1 ) to calculate the fiber content of the finished product (that is, the fiber content of the carbon-carbon composite product).
成品的碳纤维含量/％＝[预制体初始重量×(第二产物体积/第一产物体积)]/成品质量×100％ 式(1)Carbon fiber content of finished product/%=[initial weight of preform × (volume of second product/volume of first product)]/quality of finished product × 100% Formula (1)
实施例1Example 1
(1)化学气相渗透处理：将碳纤维预制体装入等温CVI炉中进行预增密，设置天然气流量为650L/min、压强为3.5kPa、温度为1095℃、工艺时长为300h，沉积工艺完成后出炉，获得平均密度为1.16g/cm3的第一产物；(1) Chemical vapor infiltration treatment: put the carbon fiber preform into an isothermal CVI furnace for pre-densification, set the natural gas flow rate to 650L/min, the pressure to 3.5kPa, the temperature to 1095°C, and the process duration to be 300h. After the deposition process is completed Out of the furnace, thefirst product with an average density of 1.16g/cm was obtained;
(2)成型处理：将预增密后的第一产物按照图纸进行机加处理，得到第二产物，第二产物的密度为1.1g/cm3；(2) Forming treatment: the first product after pre-densification is machined according to the drawings to obtain the second product, and the density of the second product is 1.1g/cm3 ;
(3)化学气相反应处理：将步骤(2)机加后尺寸合格后的第二产物装入等温CVI炉中进行一体化沉积及涂层，设置两段式工艺，其中第一段为化学气相渗透增密处理，第二段为化学气相沉积封孔涂层处理，具体地：(3) Chemical vapor phase reaction treatment: put the second product after step (2) machining into qualified size into an isothermal CVI furnace for integrated deposition and coating, and set up a two-stage process, in which the first stage is chemical vapor phase Infiltration densification treatment, the second stage is chemical vapor deposition sealing coating treatment, specifically:
第一段工艺为增密工艺：天然气流量Qf1为650L/min、压强P1为3.5kPa、温度为1095℃、工艺时长为100h，稀释气体：反应气的流量比为0：1；第二段工艺为涂层工艺：天然气流量Qf2为350L/min、氮气流量为150L/min，压强P2为1.8kPa、温度为1095℃、工艺时长为30h，稀释气体：反应气的流量比为0.43：1；待两段工艺完成后出炉，获得平均密度为1.36g/cm3的第三产物；The first stage process is densification process: natural gas flow rate Qf1 is 650L/min, pressureP1 is 3.5kPa, temperature is 1095°C, process duration is 100h, and the flow ratio of dilution gas: reaction gas is 0:1; the second stage The stage process is a coating process: natural gas flow rate Qf2 is 350L/min, nitrogen flow rate is 150L/min, pressureP2 is 1.8kPa, temperature is 1095°C, process duration is 30h, and the flow ratio of dilution gas: reaction gas is 0.43 : 1; after the completion of the two-stage process, it is discharged to obtain the third product with an average density of 1.36g/cm3 ;
其中，两段工艺中天然气流量减少量Qf1-Qf2为300L/min，天然气流量降低速率为3(L/min)/h；压强降低量P1-P2为1.7kPa，压强降低速率为0.17kPa/h；2段化学气相反应处理的总时间为130h；Among them, the natural gas flow reduction Qf1 -Qf2 in the two-stage process is 300L/min, and the natural gas flow reduction rate is 3(L/min)/h; the pressure reduction P1 -P2 is 1.7kPa, and the pressure reduction rate is 0.17kPa/h; the total time of the two-stage chemical gas phase reaction treatment is 130h;
(4)石墨化处理：工艺条件为：在惰性气氛下，石墨化温度为2200℃，反应时间为4h；(4) Graphitization treatment: the process conditions are: in an inert atmosphere, the graphitization temperature is 2200°C, and the reaction time is 4h;
(5)检查产品外观缺陷、尺寸、密度、涂层等是否合格，包装入库。(5) Check whether the appearance defect, size, density, coating, etc. of the product are qualified, and pack it into the warehouse.
本实施例步骤(1)所得第一产物和步骤(2)所得第二产物的外观照片如图2所示；步骤(3)所得第三产物的外观照片如图3所示。可以看出图3中经过沉积和涂层一体化工艺的第三产物的表面平滑、均匀，无结焦炭黑现象，且致密度显著提高。The appearance photos of the first product obtained in step (1) and the second product obtained in step (2) of this embodiment are shown in Figure 2; the appearance photos of the third product obtained in step (3) are shown in Figure 3. It can be seen that the surface of the third product after the deposition and coating integration process in Figure 3 is smooth and uniform, without coking black phenomenon, and the density is significantly improved.
制备所得碳-碳复合材料产品的纤维含量为33.3重量％，复合材料的平均密度为1.35g/cm3；任意两处位置的密度差为0.03g/cm3以下，具体地，在厚度为30mm(0mm＜H≤30mm)的规则形状复合材料产品的一侧表面、芯部以及另一侧对应的表面分别取样(取样规格：55mm×10mm×5mm)：记为A1(表面)、A2(芯部)、A3(表面)，将每个位置处取样样品的平均密度、表面到芯部的距离差(h，mm)和最大密度差(M，g/cm3)列于下表1中。本实施例以表面与芯部两处位置的密度差作为整个样品的最大密度差M。The fiber content of the prepared carbon-carbon composite product is 33.3% by weight, and the average density of the composite material is 1.35g/cm3 ; the density difference between any two positions is 0.03g/cm3 or less, specifically, when the thickness is 30mm (0mm<H≤30mm) one side surface, the core and the corresponding surface on the other side of the regular shape composite product are sampled respectively (sampling specification: 55mm×10mm×5mm): denoted as A1 (surface), A2 (core Part), A3 (surface), the average density of the samples taken at each position, the distance difference from the surface to the core (h, mm) and the maximum density difference (M, g/cm3 ) are listed in Table 1 below. In this embodiment, the density difference between the surface and the core is taken as the maximum density difference M of the entire sample.
表1Table 1
表1中，复合材料表面取样的A3与A1分别与芯部A2进行密度差计算，取两个密度差之间的最大值作为M。表1中样品中心点的距离差h的正负值表示与芯部相对应的两个方向。In Table 1, the density difference between A3 and A1 sampled on the surface of the composite material and the core A2 is calculated respectively, and the maximum value between the two density differences is taken as M. The positive and negative values of the distance difference h of the sample center point in Table 1 represent the two directions corresponding to the core.
表1中数据说明：在厚度为30mm(0mm＜H≤30mm)的复合材料产品中，任意两处位置的密度差为0.03g/cm3以下。The data in Table 1 shows that in a composite material product with a thickness of 30mm (0mm<H≤30mm), the density difference between any two positions is below 0.03g/cm3 .
实施例2Example 2
本实施例与实施例1的不同之处在于：在步骤(3)的化学气相反应处理中，将步骤(2)机加后尺寸合格后的第二产物装入等温CVI炉中进行一体化沉积及涂层，设置三段式工艺，其中第一段和第二段为化学气相渗透增密处理，第三段为化学气相沉积封孔涂层处理，具体地：The difference between this example and Example 1 is that in the chemical vapor phase reaction treatment of step (3), the second product after step (2) machined and qualified in size is loaded into an isothermal CVI furnace for integrated deposition And coating, set up a three-stage process, in which the first and second stages are chemical vapor infiltration densification treatment, and the third stage is chemical vapor deposition sealing coating treatment, specifically:
第一段的工艺条件包括：天然气流量为800L/min、氮气流量为200L/min、压强为4.6kPa、温度为1095℃、工艺时长为50h，稀释气体：反应气的流量比为0.25：1；The process conditions of the first stage include: the flow rate of natural gas is 800L/min, the flow rate of nitrogen gas is 200L/min, the pressure is 4.6kPa, the temperature is 1095°C, the process time is 50h, and the flow ratio of dilution gas: reaction gas is 0.25:1;
第二段工艺条件包括：天然气流量为600L/min、氮气流量为150L/min、压强为3.3kPa、温度为1095℃、工艺时长为50h，稀释气体和反应气体的总流量计，稀释气体流量占比为0.25：1；The process conditions of the second stage include: the flow rate of natural gas is 600L/min, the flow rate of nitrogen gas is 150L/min, the pressure is 3.3kPa, the temperature is 1095°C, the process time is 50h, the total flow meter of dilution gas and reaction gas, the flow rate of dilution gas accounts for The ratio is 0.25:1;
第三段工艺条件包括：天然气流量为300L/min、氮气流量为150L/min、压强为1.9kPa、温度为1095℃、工艺时长为30h，稀释气体和反应气体的总流量计，稀释气体流量占比为0.5：1；The process conditions of the third stage include: the flow rate of natural gas is 300L/min, the flow rate of nitrogen gas is 150L/min, the pressure is 1.9kPa, the temperature is 1095°C, the process time is 30h, the total flow meter of dilution gas and reaction gas, the flow rate of dilution gas accounts for The ratio is 0.5:1;
其中第一段与第二段工艺之间：天然气流量差为200L/min，天然气流量降低速率为4(L/min)/h；压强降低量为1.3kPa，压强降低速率为0.026kPa/h；Among them, between the first stage and the second stage process: the natural gas flow difference is 200L/min, the natural gas flow rate is 4(L/min)/h; the pressure drop is 1.3kPa, and the pressure drop rate is 0.026kPa/h;
第二段与第三段工艺之间：天然气流量差为300L/min，天然气流量降低速率为6(L/min)/h；压强差为1.4kPa，压强降低速率为0.028kPa/h；Between the second stage and the third stage process: the natural gas flow rate difference is 300L/min, the natural gas flow rate decrease rate is 6(L/min)/h; the pressure difference is 1.4kPa, and the pressure decrease rate rate is 0.028kPa/h;
三段化学气相反应处理的总时间为130h。其余过程与实施例1相同。The total time of the three-stage chemical gas phase reaction treatment is 130h. All the other processes are the same as in Example 1.
制备所得碳-碳复合材料产品的纤维含量为31.6重量％，复合材料的平均密度为1.42g/cm3；任意两处位置的密度差为0.11g/cm3以下，具体地，在厚度为50mm(30mm＜H≤60mm)的规则形状复合材料的一侧表面、芯部以及另一侧对应的表面分别取样(取样规格：55mm×10mm×5mm)：记为B1(表面)、B2(芯部)、B3(表面)，将每个位置处取样样品的平均密度、表面到芯部的距离差(h/mm)和最大密度差(M/g/cm3)列于下表2中。本实施例以表面与芯部两处位置的密度差作为整个样品的最大密度差。The fiber content of the prepared carbon-carbon composite product is 31.6% by weight, and the average density of the composite material is 1.42g/cm3 ; the density difference between any two positions is 0.11g/cm3 or less, specifically, when the thickness is 50mm (30mm<H≤60mm) one side surface, the core and the corresponding surface on the other side of the regular shape composite material are sampled separately (sampling specification: 55mm×10mm×5mm): denoted as B1 (surface), B2 (core ), B3 (surface), the average density of samples taken at each position, the distance difference (h/mm) and the maximum density difference (M/g/cm3 ) from the surface to the core are listed in Table 2 below. In this embodiment, the density difference between the surface and the core is taken as the maximum density difference of the entire sample.
表2Table 2
其中，复合材料表面取样的B3与B1分别与芯部B2进行密度差计算，取两个密度差之间的最大值作为M。Among them, B3 and B1 sampled on the surface of the composite material are respectively calculated for the density difference with the core B2, and the maximum value between the two density differences is taken as M.
表2中数据说明：在厚度为50mm(30mm＜H≤60mm)的复合材料产品中，任意两处位置的密度差为0.11g/cm3以下。The data in Table 2 shows that in a composite material product with a thickness of 50mm (30mm<H≤60mm), the density difference between any two positions is below 0.11g/cm3 .
实施例3Example 3
本实施例与实施例1的不同之处在于：The difference between this embodiment and embodiment 1 is:
在步骤(1)的化学气相渗透处理中，将碳纤维预制体装入等温CVI炉中进行预增密，设置天然气流量为900L/min、压强为4.6kPa、温度为1100℃、工艺时长为180h，沉积工艺完成后出炉，获得平均密度为1.27g/cm3的第一产物。其余过程与实施例1相同。In the chemical vapor infiltration treatment of step (1), put the carbon fiber preform into an isothermal CVI furnace for pre-densification, set the natural gas flow rate to 900L/min, the pressure to 4.6kPa, the temperature to 1100°C, and the process duration to 180h. After the deposition process is completed, the first product with an average density of 1.27 g/cm3 is obtained. All the other processes are the same as in Example 1.
制备所得碳-碳复合材料产品的纤维含量为30重量％，复合材料的平均密度为1.50g/cm3；分别获得厚度为30mm、40mm和70mm的三种厚度复合材料；其中厚度为30mm复合材料产品任意两处位置的密度差为0.01g/cm3以下；厚度为40mm的复合材料产品任意两处位置的密度差为0.06g/cm3以下；厚度为70mm的复合材料产品任意两处位置的密度差为0.12g/cm3以下。The fiber content of the prepared carbon-carbon composite product is 30% by weight, and the average density of the composite material is 1.50g/cm3 ; three kinds of thickness composite materials with a thickness of 30mm, 40mm and 70mm are obtained respectively; wherein the thickness is 30mm composite material The density difference between any two positions of the product is less than 0.01g/cm3 ; the density difference between any two positions of the composite material product with a thickness of 40mm is less than 0.06g/cm3 ; the density difference between any two positions of the composite material product with a thickness of 70mm The density difference is 0.12g/cm3 or less.
具体地，取样方式和密度差计算方式与实施例1中相同，30mm复合材料产品取样分别为A1(表面)、A2(芯部)、A3(表面)；40mm复合材料产品取样分别为B1(表面)、B2(芯部)、B3(表面)；70mm复合材料产品取样分别为C1(表面)、C2(芯部)、C3(表面)。每个位置处取样样品的平均密度、表面到芯部的距离差(h/mm)和最大密度差(M/g/cm3)列于下表3中。Specifically, the sampling method and the density difference calculation method are the same as in Example 1, and the sampling of the 30mm composite material product is respectively A1 (surface), A2 (core), and A3 (surface); the sampling of the 40mm composite material product is respectively B1 (surface) ), B2 (core), B3 (surface); 70mm composite material product samples are C1 (surface), C2 (core), and C3 (surface). The average density, surface-to-core distance difference (h/mm) and maximum density difference (M/g/cm3 ) of the samples taken at each position are listed in Table 3 below.
表3table 3
表3中数据说明：Data description in Table 3:
在厚度为30mm(0mm＜H≤30mm)的复合材料产品中，任意两处位置的密度差M为0.01g/cm3以下；In a composite material product with a thickness of 30mm (0mm<H≤30mm), the density difference M between any two positions is 0.01g/cm3 or less;
在厚度为40mm(30mm＜H≤60mm)的复合材料产品中，任意两处位置的密度差M为0.06g/cm3以下；In a composite material product with a thickness of 40mm (30mm<H≤60mm), the density difference M between any two positions is 0.06g/cm3 or less;
在厚度为70mm(60mm＜H≤100mm)的复合材料产品中，任意两处位置的密度差M为0.12g/cm3以下。In a composite material product with a thickness of 70mm (60mm<H≤100mm), the density difference M between any two positions is below 0.12g/cm3 .
将本实施例与实施例1进行比较可知：本实施例在步骤(1)的化学气相渗透处理中的工艺参数满足本公开限定的优选的参数范围，当厚度范围相同时，产品任意两处位置的密度差更低，产品表面与芯部的密度差更小。Comparing this embodiment with Example 1 shows that: the process parameters in the chemical vapor infiltration treatment in step (1) of this embodiment meet the preferred parameter range defined by the present disclosure. When the thickness range is the same, any two positions of the product The density difference is lower, and the density difference between the product surface and the core is smaller.
实施例4Example 4
本实施例与实施例1的不同之处在于：在步骤(3)的化学气相反应处理中不进行多段式处理，仅包括一段处理工艺，具体包括：The difference between this embodiment and Example 1 is that: in the chemical vapor phase reaction treatment of step (3), multistage treatment is not carried out, and only one stage of treatment process is included, specifically including:
天然气流量为500L/min、氮气流量为250L/min、压强为2.8kPa、温度为1095℃、工艺时长为100h。其余过程与实施例1相同。The natural gas flow rate is 500L/min, the nitrogen flow rate is 250L/min, the pressure is 2.8kPa, the temperature is 1095°C, and the process time is 100h. All the other processes are the same as in Example 1.
产品外观照片如图4所示。图4中产物存在明显炭黑现象，且可以看出具有明显的预制体纤维纹路，致密度不高。The photo of the product appearance is shown in Figure 4. The product in Figure 4 has obvious carbon black phenomenon, and it can be seen that it has obvious preform fiber lines, and the density is not high.
制备所得碳-碳复合材料产品的纤维含量为34.6重量％，复合材料的平均密度为1.31g/cm3；任意两处位置的密度差为0.07g/cm3以下(复合材料产品厚度为30mm)，取样方式和密度差计算方式与实施例1中相同，将每个位置处取样样品的平均密度、表面到芯部的距离差(h/mm)和最大密度差(M/g/cm3)列于下表4中。The fiber content of the prepared carbon-carbon composite product is 34.6% by weight, and the average density of the composite material is 1.31g/cm3 ; the density difference between any two positions is 0.07g/cm3 or less (the thickness of the composite material product is 30mm) , the sampling method and the density difference calculation method are the same as in Example 1, and the average density, the surface-to-core distance difference (h/mm) and the maximum density difference (M/g/cm3 ) of the sample sampled at each position are are listed in Table 4 below.
表4Table 4
表4中数据说明：在厚度为30mm(0mm＜H≤30mm)的复合材料产品中，任意两处位置的密度差M为0.07g/cm3以下。The data in Table 4 shows that in a composite material product with a thickness of 30mm (0mm<H≤30mm), the density difference M between any two positions is below 0.07g/cm3 .
将实施例4与实施例1进行比较可知：实施例1中在步骤(3)的化学气相反应处理中进行二段式处理，所得复合材料表面平滑、均匀，无结焦炭黑现象，且致密度显著提高；并且产品任意两处位置的密度差更低，产品表面与芯部的密度差更小。Comparing Example 4 with Example 1, it can be seen that: in Example 1, two-stage treatment is carried out in the chemical gas phase reaction treatment of step (3), and the surface of the obtained composite material is smooth and uniform, without coking black phenomenon, and dense Significantly improved; and the density difference between any two positions of the product is lower, and the density difference between the product surface and the core is smaller.
实施例5Example 5
本实施例与实施例1的不同之处在于：在步骤(3)的化学气相反应处理中，将步骤(2)机加后尺寸合格后的第二产物装入等温CVI炉中进行一体化沉积及涂层，设置一段式工艺：The difference between this example and Example 1 is that in the chemical vapor phase reaction treatment of step (3), the second product after step (2) machined and qualified in size is loaded into an isothermal CVI furnace for integrated deposition And coating, set a one-stage process:
工艺条件包括：天然气流量为650L/min、压强为3.5kPa、温度为1095℃、工艺时长为130h；Process conditions include: natural gas flow rate of 650L/min, pressure of 3.5kPa, temperature of 1095°C, process duration of 130h;
其余过程与实施例1相同。All the other processes are the same as in Example 1.
产品外观照片如图5a和5b所示，可以看出本实施例制备得到的产物存在明显炭黑现象，且可以看出具有明显的预制体纤维纹路，致密度不高，产品效果较差。The appearance photos of the product are shown in Figures 5a and 5b. It can be seen that the product prepared in this example has obvious carbon black phenomenon, and it can be seen that it has obvious preform fiber lines, the density is not high, and the product effect is poor.
制备所得碳-碳复合材料产品的纤维含量为33.5重量％，复合材料的平均密度为1.34g/cm3；任意两处位置的密度差为0.07g/cm3以下，取样方式和密度差计算方式与实施例1中相同(复合材料产品厚度为30mm)，将每个位置处取样样品的平均密度、表面到芯部的距离差(h/mm)和最大密度差(M/g/cm3)列于下表5中。The fiber content of the prepared carbon-carbon composite product is 33.5% by weight, and the average density of the composite material is 1.34g/cm3 ; the density difference between any two positions is less than 0.07g/cm3 , the sampling method and the calculation method of the density difference Same as in Example 1 (compositeproduct thickness is 30mm), the average density, the distance difference (h/mm) and the maximum density difference (M/g/cm ) of the sample sampled at each position place are listed in Table 5 below.
表5table 5
表5中数据说明：在厚度为30mm(0mm＜H≤30mm)的复合材料产品中，任意两处位置的密度差M为0.07g/cm3以下。The data in Table 5 shows that in a composite material product with a thickness of 30mm (0mm<H≤30mm), the density difference M between any two positions is below 0.07g/cm3 .
将本实施例与实施例1进行比较可知：实施例1中在步骤(3)的化学气相反应处理中采用的工艺参数满足第二段工艺的天然气流量和压强小于第一段工艺，得到的复合材料产物表面平滑、均匀，无结焦炭黑现象，且致密度显著提高；并且产品任意两处位置的密度差更低，产品表面与芯部的密度差更小。Comparing this embodiment with Example 1 shows that: the process parameters adopted in the chemical gas phase reaction treatment of step (3) in Example 1 meet the natural gas flow rate and pressure of the second stage process less than the first stage process, and the obtained compound The surface of the material product is smooth and uniform, without coke black phenomenon, and the density is significantly improved; and the density difference between any two positions of the product is lower, and the density difference between the product surface and the core is smaller.
实施例6Example 6
采用与实施例1相同的工艺，与实施例1的不同之处在于：将碳纤维预制体替换为密度为0.5g/cm3的碳化硅预制体。Using the same process as in Example 1, the difference from Example 1 is that the carbon fiber preform is replaced by a silicon carbide preform with a density of 0.5 g/cm3 .
其余过程与实施例1相同。制备所得碳-碳复合材料产品的纤维含量为32.2重量％，复合材料的平均密度为1.4g/cm3；任意两处位置的密度差为0.05g/cm3以下(复合材料产品厚度为30mm)，取样方式和密度差计算方式与实施例1中相同，将每个位置处取样样品的平均密度、表面到芯部的距离差(h/mm)和最大密度差(M/g/cm3)列于下表6中。All the other processes are the same as in Example 1. The fiber content of the prepared carbon-carbon composite product is 32.2% by weight, and the average density of the composite material is 1.4g/cm3 ; the density difference between any two positions is 0.05g/cm3 or less (the thickness of the composite material product is 30mm) , the sampling method and the density difference calculation method are the same as in Example 1, and the average density, the surface-to-core distance difference (h/mm) and the maximum density difference (M/g/cm3 ) of the sample sampled at each position are are listed in Table 6 below.
表6Table 6
表6中数据说明：在厚度为30mm(0mm＜H≤30mm)的复合材料产品中，任意两处位置的密度差M均为0.05g/cm3以下。The data in Table 6 shows that in a composite material product with a thickness of 30mm (0mm<H≤30mm), the density difference M between any two positions is below 0.05g/cm3 .
对比例1Comparative example 1
采用包括预制体成型→多周期增密→高温石墨化→机加成型→涂层的常规工艺方法制备得到碳碳复合材料，具体包括：Carbon-carbon composite materials are prepared by conventional processes including preform forming→multi-cycle densification→high-temperature graphitization→machining→coating, including:
(1)化学气相渗透处理：将碳纤维预制体装入等温CVI炉中进行预增密，设置天然气流量650L/min、压强3.5kPa、温度1095℃、工艺时长300h，沉积工艺完成后出炉，获得密度为1.13g/cm3的第一产物；(1) Chemical vapor infiltration treatment: put the carbon fiber prefabricated body into an isothermal CVI furnace for pre-densification, set the natural gas flow rate to 650L/min, the pressure to 3.5kPa, the temperature to 1095°C, and the process duration to be 300h. Be the first product of 1.13g/cm3 ;
(2)多周期增密处理；采用二步增密处理方式(将步骤(1)作为一步增密处理)，将第一产物装入等温CVI炉中进行二次沉积，工艺设置条件为：天然气流量为650L/min、压强P1为3.5kPa、温度为1095℃、工艺时长为300h；工艺完成后出炉，获得平均密度为1.41g/cm3的第三产物；(2) Multi-cycle densification treatment; using a two-step densification treatment method (step (1) as a one-step densification treatment), the first product is loaded into an isothermal CVI furnace for secondary deposition, and the process setting conditions are: natural gas The flow rate is 650L/min, the pressureP1 is 3.5kPa, the temperature is 1095°C, and the process time is 300h; after the process is completed, the third product with an average density of 1.41g/cm3 is obtained;
(3)石墨化处理：工艺条件为：在惰性气氛下，石墨化温度为2200℃，反应时间为4h；(3) Graphitization treatment: the process conditions are: in an inert atmosphere, the graphitization temperature is 2200°C, and the reaction time is 4h;
(4)成型处理：将预增密后的第一产物按照图纸进行机加处理，得到第二产物，第二产物的密度为1.31g/cm3；(4) Forming treatment: the first product after pre-densification is machined according to the drawings to obtain the second product, and the density of the second product is 1.31g/cm3 ;
(5)封孔涂层处理：将机加后尺寸合格的第二产物973kg装入等温CVI炉中进行封孔涂层，天然气流量Qf1为350L/min、压强P1为2.2kPa、温度为1095℃、工艺时长为40h，得到第三产物(5) Sealing coating treatment: put 973 kg of the second product with qualified size after machining into an isothermal CVI furnace for sealing coating, the natural gas flow rateQf1 is 350L/min, the pressureP1 is 2.2kPa, and the temperature is 1095°C, the process time is 40h, and the third product is obtained
(5)检查产品外观缺陷、尺寸、密度、涂层等是否合格，包装入库。本对比例得到的普通工艺第三产物的外观照片如图6a和图6b所示，可以看出产品表面具有较为明显的预制体纹路，说明致密度不高，产品效果较差。(5) Check whether the appearance defect, size, density, coating, etc. of the product are qualified, and pack it into the warehouse. The photos of the appearance of the third product of the common process obtained in this comparative example are shown in Figure 6a and Figure 6b. It can be seen that the surface of the product has relatively obvious prefabricated body lines, indicating that the density is not high and the product effect is poor.
制备所得碳-碳复合材料产品的纤维含量为33重量％，复合材料的平均密度为1.36g/cm3；获取厚度为30mm、40mm和70mm的复合材料，取样方式和密度差计算方式与实施例1中相同，将每个位置处取样样品的平均密度、表面到芯部的距离差(h/mm)和最大密度差(M/g/cm3)列于下表7中。The fiber content of the prepared carbon-carbon composite product is 33% by weight, and the average density of the composite material is 1.36g/cm3 ; to obtain composite materials with a thickness of 30mm, 40mm and 70mm, the sampling method and the calculation method of density difference are the same as in the examples 1, the average density, distance difference (h/mm) and maximum density difference (M/g/cm3 ) of the samples taken at each position are listed in Table 7 below.
表7Table 7
表7中数据说明：Data description in Table 7:
在厚度为30mm(0mm＜H≤30mm)的复合材料产品中，任意两处位置的密度差M为0.07g/cm3以下；在厚度为40mm(30mm＜H≤60mm)的复合材料产品中，任意两处位置的密度差M为0.18g/cm3以下；在厚度为70mm(60mm＜H≤100mm)的复合材料产品中，任意两处位置的密度差M为0.56g/cm3以下。In a composite material product with a thickness of 30mm (0mm<H≤30mm), the density difference M between any two positions is below 0.07g/cm3 ; in a composite material product with a thickness of 40mm (30mm<H≤60mm), The density difference M between any two positions is 0.18g/cm3 or less; in a composite material product with a thickness of 70mm (60mm<H≤100mm), the density difference M between any two positions is 0.56g/cm3 or less.
将对比例1与实施例进行比较可知：实施例中采用本公开提供的方法，得到的碳碳复合材料产品任意两处位置的密度差更低，产品表面与芯部的密度差更小。Comparing Comparative Example 1 with the Example, it can be seen that the method provided in the present disclosure is adopted in the Example, and the density difference between any two positions of the obtained carbon-carbon composite product is lower, and the density difference between the surface and the core of the product is smaller.
另外对比例1在制备工艺中，在化学气相渗透处理后，需要进行步骤(1)～(2)的多周期增密处理(总时间为600h)，然后石墨化处理和成型处理再进行封孔涂层处理，不仅多周期增密和涂层形成的总周期长(约为640h)，另外增密和涂层分步进行也额外增加了拆装炉的操作，增加了工作量。因此采用本公开提供的方法在一个工艺周内期(150h以内)即可实现增密和形成涂层，显著缩短了工艺时间，提高生产效率。In addition, in the preparation process of Comparative Example 1, after the chemical vapor infiltration treatment, multi-cycle densification treatment of steps (1) to (2) is required (total time is 600h), and then graphitization treatment and molding treatment are performed before sealing Coating treatment, not only the total period of multi-cycle densification and coating formation is long (about 640h), but also the step-by-step process of densification and coating also increases the operation of the disassembly furnace and increases the workload. Therefore, by adopting the method provided by the present disclosure, densification and coating can be realized within one process period (within 150 hours), which significantly shortens the process time and improves production efficiency.
以上结合附图详细描述了本公开的优选实施方式，但是，本公开并不限于上述实施方式中的具体细节，在本公开的技术构思范围内，可以对本公开的技术方案进行多种简单变型，这些简单变型均属于本公开的保护范围。The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure. These simple modifications all belong to the protection scope of the present disclosure.
另外需要说明的是，在上述具体实施方式中所描述的各个具体技术特征，在不矛盾的情况下，可以通过任何合适的方式进行组合。为了避免不必要的重复，本公开对各种可能的组合方式不再另行说明。In addition, it should be noted that the various specific technical features described in the above specific implementation manners may be combined in any suitable manner if there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not further described in this disclosure.
此外，本公开的各种不同的实施方式之间也可以进行任意组合，只要其不违背本公开的思想，其同样应当视为本公开所公开的内容。In addition, various implementations of the present disclosure can be combined arbitrarily, as long as they do not violate the idea of the present disclosure, they should also be regarded as the content disclosed in the present disclosure.
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| CN202210674893.2ACN116693310A (en) | 2022-06-14 | 2022-06-14 | A kind of carbon-carbon composite material and preparation method thereof |
| PCT/CN2023/077989WO2023241092A1 (en) | 2022-06-14 | 2023-02-23 | Carbon-carbon composite material and preparation method therefor |
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| CN202210674893.2ACN116693310A (en) | 2022-06-14 | 2022-06-14 | A kind of carbon-carbon composite material and preparation method thereof |
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| WO (1) | WO2023241092A1 (en) |
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