Disclosure of Invention
In view of the above, the present invention proposes a high strength rod-shaped porcelain insulator and a method for manufacturing the same to solve the above-mentioned problems.
The high-strength rod-shaped porcelain insulator is realized by the following raw materials, by weight, 50-70 parts of alumina, 20-30 parts of feldspar powder, 10-20 parts of mullite powder, 20-40 parts of alumina powder, 5-20 parts of silica micropowder, 5-15 parts of boron nitride powder, 10-20 parts of tourmaline powder, 5-10 parts of semi-carbonized straw fiber, 5-15 parts of black phosphorus powder and 5-10 parts of diethyl succinate;
The semi-carbonized straw fiber is obtained by performing pyrolysis treatment on straw under the anaerobic condition.
Further, the semi-carbonized straw fiber is prepared by cleaning straw, pretreating, crushing the straw after pretreatment to obtain short straw material, adding the short straw material into pyrolysis equipment, pyrolyzing under an anaerobic condition, cooling after pyrolysis is completed, and collecting the semi-carbonized straw fiber.
Further, the solution temperature is 325-330 ℃.
Further, the pretreatment method of the straw comprises the steps of adding the straw into a nitric acid aqueous solution for soaking for 10-12h, and stirring the straw once every 2.0-2.5h in the soaking process.
Further, the mass concentration of the aqueous solution of nitric acid is 50-60wt%.
Further, the tourmaline powder consists of magnesium tourmaline powder, iron tourmaline powder and chromium tourmaline powder with the mass ratio of (2.0-4.0): (1.0-2.5): (0.5-1.7).
Further, the straw is one of wheat straw, corn straw, sesame straw and rice straw.
Further, the preparation method of the high-strength rod-shaped porcelain insulator comprises the following steps:
S1, weighing bauxite, feldspar powder, mullite powder, alumina powder, silicon dioxide micropowder, boron nitride powder, tourmaline powder, semi-carbonized straw fibers, black phosphorus powder and diethyl succinate according to parts by weight, mixing, and adding water into a ball mill for ball milling to form slurry;
s2, pouring the slurry into a mould, and manufacturing a blank of the rod-shaped porcelain insulator through a compression molding process;
s3, immersing the green body in glaze melt for 30-60S, placing the green body into a gas kiln for sintering after glaze immersion, and naturally cooling after sintering to obtain the rod-shaped porcelain insulator.
Further, the molding pressure of the S2 medium-pressure molding process is 50-100MPa, and the molding time is 15-25min.
Further, the sintering temperature in the step S3 is 1200-1400 ℃ and the sintering time is 12-18h.
Compared with the prior art, the semi-carbonized straw fiber has the beneficial effects that the semi-carbonized straw fiber is adopted in the raw material of the insulator, and part of fiber forms are reserved in the pyrolysis process of the semi-carbonized straw fiber, and the fibers are connected with ceramic particles like a bridge, so that the cohesiveness between the raw materials is enhanced. In the compression molding and sintering processes, the cohesiveness is helpful for reducing the formation of microcracks and pores and improving the density and the overall strength of the insulator. The flexibility of the semi-carbonized straw fiber enables the semi-carbonized straw fiber to absorb part of energy when the insulator is impacted or bent, and stress is dispersed through the stretching and deformation of the fiber, so that the toughness and bending strength of the insulator are improved.
The tourmaline powder adopted in the application plays a role in filling in the insulator material, can fill micro holes and defects in the material, reduces the number of stress concentration points, improves the overall density and uniformity of the material, and further improves the mechanical strength of the insulator. The addition of boron nitride also enhances the structural stability of the insulator material. Due to the good thermal stability and chemical stability, the boron nitride can still keep stable performance under high temperature, high pressure or corrosive environment, thereby ensuring the normal operation of the insulator under severe working environment. The boron nitride and tourmaline powder also have a certain synergistic enhancement effect in the insulator material. The high hardness and wear resistance provided by the boron nitride can be combined with the piezoelectric effect and the filling effect of tourmaline powder, so that the mechanical strength and durability of the insulator are improved together. In addition, the boron nitride can improve the dispersibility of tourmaline powder in the material to a certain extent, and improve the uniformity and the compactness of the whole material. Thereby ensuring that the porcelain insulator has good mechanical strength and product performance. In addition, the black phosphorus is added, so that heat in the insulator can be conducted out rapidly, breakdown caused by overheating is prevented, and breakdown voltage of the insulator is improved.
Detailed Description
In order to better understand the technical content of the present invention, the following provides specific examples to further illustrate the present invention.
The experimental methods used in the embodiment of the invention are conventional methods unless otherwise specified.
Materials, reagents, and the like used in the examples of the present invention are commercially available unless otherwise specified.
Example 1
The high-strength rod-shaped porcelain insulator comprises the following raw materials, by weight, 50 parts of bauxite, 20 parts of feldspar powder, 10 parts of mullite powder, 20 parts of alumina powder, 5 parts of silicon dioxide micro powder, 5 parts of boron nitride powder, 10 parts of tourmaline powder, 5 parts of semi-carbonized straw fibers, 5 parts of black phosphorus powder and 5 parts of diethyl succinate. The semi-carbonized straw fiber is obtained by performing pyrolysis treatment on straw under the anaerobic condition. The method comprises the following steps of cleaning the straw, adding the straw into a nitric acid aqueous solution with the mass concentration of 50wt% for soaking for 12 hours for pretreatment, and stirring the straw once every 2.5 hours in the soaking process. Crushing the straw after pretreatment to obtain short straw materials, adding the short straw materials into pyrolysis equipment, pyrolyzing the short straw materials under the conditions of no oxygen and 325 ℃, and collecting the short straw materials after cooling after pyrolysis to obtain semi-carbonized straw fibers. Wherein the tourmaline powder consists of magnesium tourmaline powder, iron tourmaline powder and chromium tourmaline powder with the mass ratio of 2.0:1.0:0.5. Wherein the straw is wheat straw.
The preparation method of the high-strength rod-shaped porcelain insulator comprises the following steps of:
S1, weighing bauxite, feldspar powder, mullite powder, alumina powder, silicon dioxide micropowder, boron nitride powder, tourmaline powder, semi-carbonized straw fibers, black phosphorus powder and diethyl succinate according to parts by weight, mixing, and adding water into a ball mill for ball milling to form slurry;
s2, pouring the slurry into a mould, and manufacturing a blank body of the rod-shaped porcelain insulator through a compression molding process. Wherein, the molding pressure is 50MPa and the molding time is 25min.
S3, immersing the green body in glaze melt for 30S, placing the green body into a gas kiln for sintering at 12000 ℃ after glaze immersion, sintering for 18h, and naturally cooling after sintering to obtain the rod-shaped porcelain insulator.
Example 2
The high-strength rod-shaped porcelain insulator comprises the following raw materials, by weight, 50 parts of bauxite, 20 parts of feldspar powder, 10 parts of mullite powder, 20 parts of alumina powder, 5 parts of silicon dioxide micro powder, 5 parts of boron nitride powder, 10 parts of tourmaline powder, 5 parts of semi-carbonized straw fibers, 5 parts of black phosphorus powder and 5 parts of diethyl succinate. The semi-carbonized straw fiber is obtained by performing pyrolysis treatment on straw under the anaerobic condition. The method comprises the following steps of cleaning the straw, adding the straw into a nitric acid aqueous solution with the mass concentration of 60wt% for soaking for 102 hours for pretreatment, and stirring the straw once every 2.0 hours in the soaking process. Crushing the straw after pretreatment to obtain short straw materials, adding the short straw materials into pyrolysis equipment, pyrolyzing the short straw materials under the conditions of no oxygen and 330 ℃, and collecting the short straw materials after cooling after pyrolysis to obtain semi-carbonized straw fibers. Wherein the tourmaline powder consists of magnesium tourmaline powder, iron tourmaline powder and chromium tourmaline powder with the mass ratio of 4.0:2.5:0.5. Wherein the straw is corn straw.
The preparation method of the high-strength rod-shaped porcelain insulator comprises the following steps of:
S1, weighing bauxite, feldspar powder, mullite powder, alumina powder, silicon dioxide micropowder, boron nitride powder, tourmaline powder, semi-carbonized straw fibers, black phosphorus powder and diethyl succinate according to parts by weight, mixing, and adding water into a ball mill for ball milling to form slurry;
S2, pouring the slurry into a mould, and manufacturing a blank body of the rod-shaped porcelain insulator through a compression molding process. Wherein, the molding pressure is 100MPa, and the molding time is 155min.
S3, immersing the green body in glaze melt for 60S, placing the green body into a gas kiln for sintering at 1400 ℃ after glaze immersion, sintering for 12h, and naturally cooling after sintering to obtain the rod-shaped porcelain insulator.
Example 3
The high-strength rod-shaped porcelain insulator comprises the following raw materials, by weight, 60 parts of bauxite, 25 parts of feldspar powder, 15 parts of mullite powder, 30 parts of alumina powder, 12 parts of silica micropowder, 10 parts of boron nitride powder, 15 parts of tourmaline powder, 8 parts of semi-carbonized straw fiber, 10 parts of black phosphorus powder and 7 parts of diethyl succinate. The semi-carbonized straw fiber is obtained by performing pyrolysis treatment on straw under the anaerobic condition. The method comprises the following steps of cleaning the straw, adding the straw into a nitric acid aqueous solution with the mass concentration of 55wt% for soaking for 11 hours for pretreatment, and stirring the straw once every 2.2 hours in the soaking process. Crushing the straw after pretreatment to obtain short straw materials, adding the short straw materials into pyrolysis equipment, pyrolyzing the short straw materials under the conditions of no oxygen and 327.5 ℃, and collecting the semi-carbonized straw fibers after cooling after pyrolysis. Wherein the tourmaline powder consists of magnesium tourmaline powder, iron tourmaline powder and chromium tourmaline powder with the mass ratio of 3.0:1.8:1.1. Wherein the straw is sesame straw.
The preparation method of the high-strength rod-shaped porcelain insulator comprises the following steps of:
S1, weighing bauxite, feldspar powder, mullite powder, alumina powder, silicon dioxide micropowder, boron nitride powder, tourmaline powder, semi-carbonized straw fibers, black phosphorus powder and diethyl succinate according to parts by weight, mixing, and adding water into a ball mill for ball milling to form slurry;
s2, pouring the slurry into a mould, and manufacturing a blank body of the rod-shaped porcelain insulator through a compression molding process. Wherein, the molding pressure is 75MPa and the molding time is 20min.
S3, immersing the green body in glaze melt for 45S, placing the green body into a gas kiln for sintering at 1300 ℃ after glaze immersion, sintering for 15h, and naturally cooling after sintering to obtain the rod-shaped porcelain insulator.
Example 4
The high-strength rod-shaped porcelain insulator comprises the following raw materials, by weight, 70 parts of bauxite, 30 parts of feldspar powder, 20 parts of mullite powder, 40 parts of alumina powder, 20 parts of silica micro powder, 15 parts of boron nitride powder, 20 parts of tourmaline powder, 10 parts of semi-carbonized straw fiber, 15 parts of black phosphorus powder and 10 parts of diethyl succinate. The semi-carbonized straw fiber is obtained by performing pyrolysis treatment on straw under the anaerobic condition. The method comprises the following steps of cleaning the straw, adding the straw into a nitric acid aqueous solution with the mass concentration of 50wt% for soaking for 12 hours for pretreatment, and stirring the straw once every 2.5 hours in the soaking process. Crushing the straw after pretreatment to obtain short straw materials, adding the short straw materials into pyrolysis equipment, pyrolyzing the short straw materials under the conditions of no oxygen and 325 ℃, and collecting the short straw materials after cooling after pyrolysis to obtain semi-carbonized straw fibers. Wherein the tourmaline powder consists of magnesium tourmaline powder, iron tourmaline powder and chromium tourmaline powder with the mass ratio of 2.0:1.0:0.5. Wherein the straw is rice straw.
The preparation method of the high-strength rod-shaped porcelain insulator comprises the following steps of:
S1, weighing bauxite, feldspar powder, mullite powder, alumina powder, silicon dioxide micropowder, boron nitride powder, tourmaline powder, semi-carbonized straw fibers, black phosphorus powder and diethyl succinate according to parts by weight, mixing, and adding water into a ball mill for ball milling to form slurry;
s2, pouring the slurry into a mould, and manufacturing a blank body of the rod-shaped porcelain insulator through a compression molding process. Wherein, the molding pressure is 50MPa and the molding time is 25min.
S3, immersing the green body in glaze melt for 30S, placing the green body into a gas kiln for sintering at 1200 ℃ after glaze immersion, sintering for 18h, and naturally cooling after sintering to obtain the rod-shaped porcelain insulator.
Example 5
The high-strength rod-shaped porcelain insulator comprises the following raw materials, by weight, 70 parts of bauxite, 30 parts of feldspar powder, 120 parts of mullite powder, 40 parts of alumina powder, 20 parts of silica micro powder, 15 parts of boron nitride powder, 20 parts of tourmaline powder, 10 parts of semi-carbonized straw fiber, 15 parts of black phosphorus powder and 10 parts of diethyl succinate. The semi-carbonized straw fiber is obtained by performing pyrolysis treatment on straw under the anaerobic condition. The method comprises the following steps of cleaning the straw, adding the straw into a nitric acid aqueous solution with the mass concentration of 60wt% for soaking for 10 hours for pretreatment, and stirring the straw once every 2.0 hours in the soaking process. Crushing the straw after pretreatment to obtain short straw materials, adding the short straw materials into pyrolysis equipment, pyrolyzing the short straw materials under the conditions of no oxygen and 330 ℃, and collecting the short straw materials after cooling after pyrolysis to obtain semi-carbonized straw fibers. Wherein the tourmaline powder consists of magnesium tourmaline powder, iron tourmaline powder and chromium tourmaline powder with the mass ratio of 4.0:2.5:1.7. Wherein the straw is wheat straw.
The preparation method of the high-strength rod-shaped porcelain insulator comprises the following steps of:
S1, weighing bauxite, feldspar powder, mullite powder, alumina powder, silicon dioxide micropowder, boron nitride powder, tourmaline powder, semi-carbonized straw fibers, black phosphorus powder and diethyl succinate according to parts by weight, mixing, and adding water into a ball mill for ball milling to form slurry;
s2, pouring the slurry into a mould, and manufacturing a blank body of the rod-shaped porcelain insulator through a compression molding process. Wherein, the molding pressure is 100MPa, and the molding time is 15min.
S3, immersing the green body in glaze melt for 60S, placing the green body into a gas kiln for sintering at 1400 ℃ after glaze immersion, sintering for 12h, and naturally cooling after sintering to obtain the rod-shaped porcelain insulator.
Comparative example 1
This comparative example is compared with example 3, except that the tourmaline powder is replaced with the boron nitride powder in the same amount.
Comparative example 2
This comparative example is compared with example 3, except that the same amount of tourmaline powder was used instead of boron nitride powder.
Comparative example 3
This comparative example is compared to example 3, except that the semi-carbonized straw fiber is replaced with the wheat straw fiber of equal parts by weight.
Comparative example 4
This comparative example is different from example 3 in that the raw material does not contain black phosphorus powder.
Performance detection
The flexural strength of the test specimens prepared by the methods of the examples and comparative examples was tested with reference to the requirements of standard GB/T4741-1999, the loading speed was set to 20N/s, the breakdown voltages of the test specimens prepared by the methods of the examples and comparative examples were tested by simulating lightning strike effects with a surge voltage generator, each group of test specimens was repeatedly freeze-thawed 30 times at-50 ℃ to 40 ℃, the specimens were placed in a box with a constant temperature of-50 ℃ for 20min, then were taken out and placed in the air for 10min, then were placed in a box with a constant temperature of 40 ℃ for 20min, and were taken out and placed in the air for 10min after the completion of the standing, namely, one freeze-thawing process was completed, and after 30 times of freeze thawing, whether cracks were generated on the surfaces of the specimens were observed, and the results are shown in Table 1.
| Flexural Strength/N | Impulse voltage/kV | Whether or not there are cracks after 30 times of freeze thawing |
| Example 1 | 525 | 175 | No crack |
| Example 2 | 527 | 174 | No crack |
| Example 3 | 533 | 180 | No crack |
| Example 4 | 526 | 175 | No crack |
| Example 5 | 528 | 173 | No crack |
| Comparative example 1 | 263 | 116 | Small amount of cracks |
| Comparative example 2 | 272 | 127 | Small amount of cracks |
| Comparative example 3 | 413 | 131 | Small amount of cracks |
| Comparative example 4 | 315 | 128 | Small amount of cracks |
The bending strength of the porcelain insulators of the embodiments 1-5 is in the range of 525-533MPa, which is far higher than 180-200MPa required by the traditional insulators, and the breakdown voltage is also higher, which is kept at 173-180kV. This is mainly due to the synergistic effect of the semi-carbonized straw fiber, the black phosphorus powder, the tourmaline powder and the boron nitride powder. The semi-carbonized straw fiber enhances the cohesiveness and toughness among the raw materials, and the black phosphorus powder can promote the densification of the ceramic raw materials in the sintering process, so that the density and strength of the product are improved, and the tourmaline powder and boron nitride powder improve the overall strength and stability of the insulator through the filling effect and the high hardness and wear resistance of the tourmaline powder and boron nitride powder.
After the tourmaline powder is replaced by the boron nitride powder in comparative example 1, the flexural strength and the breakdown voltage are both greatly reduced. This indicates that piezoelectric effect and filling effect of tourmaline powder have important contribution to insulator performance, and boron nitride powder alone cannot be completely replaced.
The performance of comparative example 2 was also decreased after the boron nitride powder was completely replaced with tourmaline powder, but the decrease was smaller than that of comparative example 1. This suggests that the high hardness and chemical stability of boron nitride powder also have a positive effect on insulator performance, but the role of tourmaline powder is more critical.
Examples 1 to 5 all exhibited excellent freeze-thaw resistance, and no crack was generated. This benefits from the flexibility and toughening effect of the semi-carbonized straw fiber, as well as the high compactness and uniformity of the overall material.
A small amount of cracks appear in the comparative examples 1-2, which shows that the synergistic effect of tourmaline powder and boron nitride powder is important for improving the freeze-thawing resistance of the insulator.
The insulator properties of examples 1-5 using semi-carbonized straw fibers were significantly better than comparative example 3, mainly because the organic components in the straw were partially carbonized by treatment, which maintained the fiber morphology of part of the straw, while imparting new physical and chemical properties. The semi-carbonization treatment obviously improves the flexibility, cohesiveness and thermal stability of the straw fiber, thereby enhancing the overall performance of the insulator. Comparative example 3 although the wheat straw fiber also has a certain reinforcing effect, the performance thereof is still greatly different from that of the semi-carbonized straw fiber.
Examples 1-5 are superior to comparative example 4 in flexural strength, breakdown voltage and freeze-thaw resistance. This is because the black phosphorus powder can form an effective reinforcing phase. When the insulator is subjected to bending stress, the black phosphorus powder particles can effectively bear partial stress, so that the crack propagation is delayed, and the bending strength of the porcelain insulator is improved. In the insulator, the thickness and uniformity of the electric insulating layer of the insulator can be increased by adding the black phosphorus powder, so that the breakdown voltage of the insulator is improved. When the insulator is subjected to high voltage, the black phosphorus powder particles can form a barrier to prevent the current from breaking down the inside of the porcelain insulator. In addition, the addition of the black phosphorus powder can improve the microstructure of the insulator and increase the porosity and specific surface area inside the insulator. The pores and the specific surface area are favorable for permeation and discharge of water molecules, and when the insulator is subjected to a freeze-thawing cycle, the black phosphorus powder particles can absorb and release the water molecules, so that damage to the insulator caused by expansion and contraction of the water is reduced. Meanwhile, the black phosphorus powder has better thermal stability and is not easy to generate phase change or decomposition due to temperature change. In the insulator, the addition of the black phosphorus powder can improve the overall thermal stability of the insulator, so that the insulator can still maintain better performance under the extreme temperature condition.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.