Single step or multistep reinforcement application and preparation are in the devitrified glass of 5G communication mobile terminalsTechnical field
The invention belongs to the technical fields of devitrified glass, are related to electron display device protecgulum and rear cover material, specifically relate toAnd a kind of chemical enhancement methods of zeopan devitrified glass, and in particular to single step or multistep reinforcement application and preparation are logical in 5GBelieve the devitrified glass of mobile terminal.
Background technology
With the development of modern science and technology, electron display device renewal speed is accelerated, the requirement of lighting, the change of 5G communicationsThe application of leather, wireless charging, protecgulum and rear cover material for display device propose harsher requirement.
The protecgulum of electron display device uses import or domestic high lead glass currently on the market, although the glass shock resistance is strongDegree is compared common soda-lime-silica glass and is promoted, but user's broken screen problem in occurs repeatedly.In addition, being carried in impact strengthUnder the premise of rising, glass surface hardness is deteriorated, more not damage resistant.Therefore, a kind of novel glass panel is developed, is had both high hardDegree, impact strength, it appears particularly important.
The traditional metal material of the rear cover generally use of display device, due to that can shield electromagnetic signal and hinder wireless chargingElectricity can not adapt to the demand of the following 5G mobile terminals and electronic equipment development, and glass material disclosure satisfy that and use theseThe electromagnetic property requirement of new technology mobile terminal, is one of the core material of the following field of mobile terminals.Currently on the marketThere is the mobile terminal product that rear cover uses high lead glass, but its mechanical property also has further room for promotion.
For this present situation, people turn one's attention to the devitrified glass with excellent mechanical performance.Devitrified glass has machineTool intensity is high, it is wear-resisting the features such as.Alumina silicate glass is carried out crystallization and thermal treatment to obtain principal crystalline phase being the transparent of spinelleDevitrified glass has higher hardness and intensity, but its impact resistance is not strong enough.
By chemical toughening method, i.e. ion exchange enhances method, can strengthen to devitrified glass.It is substantially all at presentIt is to be enhanced using the method for improving stressor layers intensity, but pass through we have discovered that if micro-crack depth is pressed more than surfaceStress layer depth, micro-crack extension will be directly across compressive stress layers.Therefore it is proposed that not only being wanted in devitrified glass Chemical enhancementConsider stressor layers intensity, should also seek a kind of chemical enhancement methods for deepening stress layer depth.Go for larger switching layerSwap time will be appropriately extended in depth, increase exchange temperature, but excessively high exchange temperature and long swap time can leadStress relaxation is caused, surface stress is reduced.Want to obtain high surface stress it is necessary to reduce exchange temperature, but that can cause to answer againPower layer depth is inadequate.According to two-step method, then this contradiction can only be solved to a certain extent, it is inadequate that there are still stress intensities,The problems such as stressor layers thickness low LCL.Therefore it should seek a kind of method that stress layer depth is taken into account with stress intensity in glass tempering.
Invention content
The purpose of the present invention is to provide a kind of intensifying method of devitrified glass, the reinforcing devitrified glass can be applied to includeThe protecgulum and back shroud of the display device of 5G communication mobile terminals.The realization of reinforcing is by using sodium/potassium/rubidium/cesium ion pairMonovalent ion in devitrified glass carries out ion exchange realization.The stress layer thickness of obtained devitrified glass is big, intensity is high,Shock resistance is good.
The present invention be realize its purpose the technical solution adopted is that：
Single step or multistep reinforcement application and preparation clean devitrified glass raw sheet in the devitrified glass of 5G communication mobile terminalsIt is placed in fused salt and is strengthened, including：
(1) it is impregnated in 410-490 DEG C of melting fused salt A and keeps the temperature 1-12h, dry after cleaning, fused salt A is by mass percentageMeter, including sodium nitrate 65-100%, potassium nitrate 0-35%, diatomite 0-3%, antimony oxide 0-2%, cerium oxide 0-0.5%；
(2) it is impregnated in 410-490 DEG C of melting fused salt B and keeps the temperature 4-24h, dry after cleaning, fused salt B is by mass percentageMeter, including potassium nitrate 65-100%, sodium nitrate 0-35%, diatomite 0-3%, antimony oxide 0-2%, potassium pyroantimonate 0-2%,Cerium oxide 0-0.5%；
(3) be immersed in 1-12h in 410-490 DEG C of melting fused salt C, it is dry after cleaning, fused salt C by mass percentage,Including rubidium nitrate 65-100%, potassium nitrate 0-35%, diatomite 0-3%, antimony oxide 0-2%, cerium oxide 0-0.5%；
(4) it is immersed in 410-490 DEG C of melting fused salt D and keeps the temperature 1-12h, dry after cleaning, fused salt D is by mass percentageMeter, including cesium nitrate 65-100%, rubidium nitrate 0-35%, diatomite 0-3%, antimony oxide 0-2%, cerium oxide 0-0.5%；
Devitrified glass raw sheet is subjected to single step reinforcing by the processing of (1) or (2) or (3) or (4), or suitable by (1), (2)Sequence carries out two step reinforcings or carries out two step reinforcings by (1), (3) sequence or carry out two step reinforcings by (1), (4) sequence or press(2), (3) sequence carries out two step reinforcings or presses (2), (4) sequence two step reinforcings of progress or strong by (3), two steps of (4) sequence progressChange or by (1), (2), (3) sequence carry out three step reinforcings or by (1), (2), (4) sequence carry out three step reinforcings or by (1),(3), (4) sequence carries out three step reinforcings or carries out three step reinforcings or (1), (2), (3), (4) sequence by (2), (3), (4) sequenceFour step reinforcings are carried out, single step is obtained or multistep strengthens the devitrified glass applied to 5G communication mobile terminals prepared.
The ingredient of the devitrified glass raw sheet includes SiO2、Al2O3、MgO、Na2O、K2O、Li2O、TiO2, ZrO, ZnO, knotContain glass phase and spinelle, and/or spodumene, and/or quartz solid solution, and/or TiO on structure2Crystalline phase, and/or A2TiO4It is brilliantPhase, and/or B2TiO5Crystalline phase, wherein A are divalent metal, such as Mg2+, Fe2+, Co2+, Ni2+, Mn2+, Zn2+Deng；B is trivalentMetal cation, such as Al3+, Fe3+, Co3+, Cr3+, Ga3+Deng.
The beneficial effects of the invention are as follows：
It is ion-exchanger to select sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, and cation radius is correspondingly greater than Li+、Na+、K+.Devitrified glass surface generates the compressive stress layer with certain depth and intensity after ion exchange so that devitrified glassMechanical property significantly increases.The devitrified glass four-point bending intensity strengthened through multistep is higher than 600MPa, and superficial hardness number is higher than700HV, surface layer value of compressive stress are more than 750MPa, and stress layer depth can be more than 100 μm, and impact strength is more than 0.3J；And single stepThe performance for strengthening devitrified glass is that four-point bending intensity is higher than 600MPa, and superficial hardness number is higher than 700HV, and surface layer value of compressive stress is bigIn 700MPa, stress layer depth is more than 40 μm, and impact strength is more than 0.2J.It can be seen that multistep strengthens the impact resistance of devitrified glassIt can significantly improve.
Rubidium, cesium ion field strength, radius are above Li+、Na+、K+Ion, after replacing monovalent ion, because extruding and field strength are formerCause is conducive to the raising of devitrified glass surface chemistry stability；Rubidium, caesium are proved to be the necessary trace element of human body, to human bodyWith it is environmentally friendly.
Simple and easy to get, the process stabilizing for preparing raw material of the present invention, has reached practical and industrialized condition.
Specific implementation mode
With reference to specific embodiment, the present invention is further illustrated.
Embodiment 1
Clean devitrified glass raw sheet is impregnated in 430 DEG C of melting fused salt (wt%)：Sodium nitrate 79%, potassium nitrate19.9%, diatomite 0.5%, antimony oxide 0.5%, cerium oxide 0.1%, middle heat preservation 10h.Obtained devitrified glass cleaning is dryAfter dry, then it is impregnated in 430 DEG C of melting fused salt (wt%)：Potassium nitrate 95%, sodium nitrate 1%, diatomite 2%, antimony oxide1%, potassium pyroantimonate 1%, cerium oxide 0.3%, middle heat preservation 6h are dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO248.2%, Al2O320.6%, Na2O 13.5%, K2O 1%,MgO 7.5%, ZrO22%, Li2O 3.7%, TiO22.5%, ZnO 1%, four-point bending intensity are 160MPa, case hardnessValue is 660HV, impact strength 0.1J.
Obtained reinforcing devitrified glass four-point bending intensity 650MPa, superficial hardness number 750HV, surface layer value of compressive stress850MPa, 108 μm of stress layer depth, impact strength 0.35J.
Embodiment 2
Clean devitrified glass raw sheet is impregnated in 430 DEG C of melting fused salt (wt%)：Sodium nitrate 85%, potassium nitrate15%, middle heat preservation 10h.After obtained devitrified glass is cleaned and dried, then it is impregnated in 430 DEG C of melting fused salt (wt%)：Rubidium nitrate91%, potassium nitrate 8%, diatomite 0.7%, cerium oxide 0.3%, middle heat preservation 6h are dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO249%, Al2O314%, Na2O 11%, K2O 1.5%, MgO2.5%, ZrO210%, Li2O 4%, TiO25%, ZnO 3%, four-point bending intensity 235Mpa, superficial hardness number are676HV, impact strength 0.15J.
Obtained reinforcing devitrified glass four-point bending intensity 680MPa, superficial hardness number 760HV, surface layer value of compressive stress870MPa, 110 μm of stress layer depth, impact strength 0.34J.
Embodiment 3
Clean devitrified glass raw sheet is impregnated in 430 DEG C of melting fused salt (wt%)：Potassium nitrate 96%, sodium nitrate 2%,Diatomite 1%, antimony oxide 0.5%, cerium oxide 0.5%, middle heat preservation 10h.After obtained devitrified glass is cleaned and dried, then soakStain is in 430 DEG C of melting fused salt (wt%)：Cesium nitrate 91%, rubidium nitrate 8%, diatomite 0.7%, cerium oxide 0.3%, middle heat preservation4h is dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO255.1%, Al2O311%, Na2O 9%, K2O 3%, MgO4%, ZrO212%, TiO21%, Li2O 2.4%, ZnO 2.5%, four-point bending intensity 253Mpa, superficial hardness number are715HV, impact strength 0.16J.
Obtained reinforcing devitrified glass four-point bending intensity 690MPa, superficial hardness number 780HV, surface layer value of compressive stress880MPa, 112 μm of stress layer depth, impact strength 0.36J.
Embodiment 4
Clean devitrified glass raw sheet is impregnated in 420 DEG C of melting fused salt (wt%)：Potassium nitrate 91%, sodium nitrate 2%,Diatomite 3%, antimony oxide 2%, potassium pyroantimonate 2%, middle heat preservation 10h.After obtained devitrified glass is cleaned and dried, then impregnateIn 430 DEG C of melting fused salt (wt%)：Rubidium nitrate 91%, potassium nitrate 8%, diatomite 0.7%, cerium oxide 0.3%, middle heat preservation6h is dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO248%, Al2O318%, Na2O 12%, K2O 1%, MgO11%, ZrO21.5%, TiO22%, Li2O 5%, ZnO 1.5%, four-point bending intensity 170Mpa, superficial hardness number are637HV, impact strength 0.10J.
Obtained reinforcing devitrified glass four-point bending intensity 660MPa, superficial hardness number 750HV, surface layer value of compressive stress850MPa, 103 μm of stress layer depth, impact strength 0.32J.
Embodiment 5
Clean devitrified glass raw sheet is impregnated in 490 DEG C of melting fused salt (wt%)：Sodium nitrate 66%, potassium nitrate28.5%, diatomite 3%, antimony oxide 2%, cerium oxide 0.5%, middle heat preservation 4h.After obtained devitrified glass is cleaned and dried,It is impregnated in 480 DEG C of melting fused salt (wt%) again：Potassium nitrate 66%, sodium nitrate 26.5%, diatomite 3%, potassium pyroantimonate 2%,Antimony oxide 2%, cerium oxide 0.5%, middle heat preservation 6h are dry after cleaning.After obtained devitrified glass is cleaned and dried, then impregnateIn 470 DEG C of melting fused salt (wt%)：Rubidium nitrate 91%, potassium nitrate 8%, diatomite 0.7%, cerium oxide 0.3%, middle heat preservation4h is dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO248%, Al2O318%, Na2O 12%, K2O 1%, MgO11%, ZrO21.5%, TiO22%, Li2O 5%, ZnO 1.5%, four-point bending intensity 170Mpa, superficial hardness number are637GPa, impact strength 0.1J.
Obtained reinforcing devitrified glass four-point bending intensity 660MPa, superficial hardness number 750HV, surface layer value of compressive stress855MPa, 115 μm of stress layer depth, impact strength 0.34J.
Embodiment 6
Clean devitrified glass raw sheet is impregnated in 430 DEG C of melting fused salt (wt%)：Sodium nitrate 66%, potassium nitrate28.5%, diatomite 3%, antimony oxide 2%, cerium oxide 0.5%, middle heat preservation 4h.After obtained devitrified glass is cleaned and dried,It is impregnated in 430 DEG C of melting fused salt (wt%) again：Potassium nitrate 91%, sodium nitrate 1.5%, diatomite 3%, potassium pyroantimonate 2%, threeAoxidize two antimony 2%, cerium oxide 0.5%, middle heat preservation 6h, drying after cleaning.After obtained devitrified glass is cleaned and dried, then it is impregnated in430 DEG C of melting fused salt (wt%)：Cesium nitrate 80%, rubidium nitrate 19%, diatomite 0.7%, cerium oxide 0.3%, middle heat preservation 4h,It is dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO257.5%, Al2O310%, Na2O 8%, K2O 2%, MgO6%, ZrO23%, Li2O 3.5%, TiO23.5%, ZnO 2.5%, P2O54%, four-point bending intensity 224Mpa, surface are hardAngle value is 666HV, impact strength 0.1J.
Obtained reinforcing devitrified glass four-point bending intensity 680MPa, superficial hardness number 760HV, surface layer value of compressive stress860MPa, 118 μm of stress layer depth, impact strength 0.37J.
Embodiment 7
Clean devitrified glass raw sheet is impregnated in 420 DEG C of melting fused salt (wt%)：Sodium nitrate 66%, potassium nitrate28.5%, diatomite 3%, antimony oxide 2%, cerium oxide 0.5%, middle heat preservation 4h.After obtained devitrified glass is cleaned and dried,It is impregnated in 420 DEG C of melting fused salt (wt%) again：Potassium nitrate 91%, sodium nitrate 1.5%, diatomite 3%, potassium pyroantimonate 2%, threeAoxidize two antimony 2%, cerium oxide 0.5%, middle heat preservation 5h, drying after cleaning.After obtained devitrified glass is cleaned and dried, then it is impregnated in420 DEG C of melting fused salt (wt%)：Rubidium nitrate 81%, potassium nitrate 18%, diatomite 0.7%, cerium oxide 0.3%, middle heat preservation 2h,It is dry after cleaning.After obtained devitrified glass is cleaned and dried, then it is impregnated in 420 DEG C of melting fused salt (wt%)：Cesium nitrate 91%,Rubidium nitrate 8%, diatomite 0.7%, antimony oxide 2%, cerium oxide 0.3%, middle heat preservation 2h are dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO264%, Al2O310%, Na2O 7%, K2O 4%, Li2O1.4%, MgO 5%, ZrO21.4%, ZnO 3.8%, TiO22.4%, P2O51%, four-point bending intensity 200Mpa, surfaceHardness number is 607HV, impact strength 0.1J.
Obtained reinforcing devitrified glass four-point bending intensity 685MPa, superficial hardness number 760HV, surface layer value of compressive stress872MPa, 115 μm of stress layer depth, impact strength 0.38J.
Embodiment 8
Clean devitrified glass raw sheet is impregnated in 430 DEG C of melting fused salt (wt%)：10h is kept the temperature in sodium nitrate 100%.After obtained devitrified glass is cleaned and dried, then it is impregnated in 430 DEG C of melting fused salt (wt%)：6h is kept the temperature in potassium nitrate 100%, clearlyIt is dry after washing.
The ingredient of the devitrified glass raw sheet is SiO249%, Al2O315%, Na2O 7%, K2O 6%, MgO 5%,ZrO22%, Li2O 2.7%, TiO23.3%, ZnO 2.0%, P2O50.5%, four-point bending intensity is 170MPa, and surface is hardAngle value is 610HV, impact strength 0.10J.
Obtained reinforcing devitrified glass four-point bending intensity 680MPa, superficial hardness number 833HV, surface layer value of compressive stress950MPa, 103 μm of stress layer depth, impact strength 0.34J.
Embodiment 9
Be impregnated in 410 DEG C of melting fused salt and keep the temperature 12h, it is dry after cleaning, fused salt by mass percentage, including nitric acidSodium 65%, potassium nitrate 32%, diatomite 1.5%, antimony oxide 1%, cerium oxide 0.5%.
The ingredient of the devitrified glass raw sheet is SiO257.5%, Al2O310%, Na2O 8%, K2O 2%, MgO6%, ZrO23%, Li2O 3.5%, TiO23.5%, ZnO 2.5%, P2O54%, four-point bending intensity 224Mpa, surface are hardAngle value is 666HV, impact strength 0.1J.
Obtained reinforcing devitrified glass four-point bending intensity 620MPa, superficial hardness number 722HV, surface layer value of compressive stress731MPa, 53 μm of stress layer depth, impact strength 0.21J.
Embodiment 10
Clean devitrified glass raw sheet is impregnated in 490 DEG C of melting fused salt and keeps the temperature 8h, fused salt by mass percentage, wrapsInclude potassium nitrate 65%, sodium nitrate 28%, diatomite 3%, antimony oxide 2%, potassium pyroantimonate 1.5%, cerium oxide 0.5%.
The ingredient of the devitrified glass raw sheet is SiO264%, Al2O310%, Na2O 7%, K2O 4%, Li2O1.4%, MgO 5%, ZrO21.4%, ZnO 3.8%, TiO22.4%, P2O51%, four-point bending intensity 200Mpa, surfaceHardness number is 607HV, impact strength 0.1J.
Obtained reinforcing devitrified glass four-point bending intensity 632MPa, superficial hardness number 731HV, surface layer value of compressive stress745MPa, 61 μm of stress layer depth, impact strength 0.22J.
Embodiment 11
Clean devitrified glass raw sheet is immersed in 12h in 410 DEG C of melting fused salt, dry after cleaning, fused salt presses qualityPercentages, including rubidium nitrate 66%, potassium nitrate 31%, diatomite 1%, antimony oxide 1.8%, cerium oxide 0.2%.
The ingredient of the devitrified glass raw sheet is SiO248%, Al2O318%, Na2O 12%, K2O 1%, MgO11%, ZrO21.5%, TiO22%, Li2O 5%, ZnO 1.5%, four-point bending intensity 170Mpa, superficial hardness number are637HV, impact strength 0.10J.
Obtained reinforcing devitrified glass four-point bending intensity 643MPa, superficial hardness number 740HV, surface layer value of compressive stress763MPa, 67 μm of stress layer depth, impact strength 0.23J.
Embodiment 12
Clean devitrified glass raw sheet is immersed in 490 DEG C of melting fused salt and keeps the temperature 7h, dry after cleaning, fused salt presses matterMeasure percentages, including cesium nitrate 90%, rubidium nitrate 7%, diatomite 1%, antimony oxide 2%.
The ingredient of the devitrified glass raw sheet is SiO248%, Al2O318%, Na2O 12%, K2O 1%, MgO11%, ZrO21.5%, TiO22%, Li2O 5%, ZnO 1.5%, four-point bending intensity 170Mpa, superficial hardness number are637HV, impact strength 0.10J.
Obtained reinforcing devitrified glass four-point bending intensity 651MPa, superficial hardness number 747HV, surface layer value of compressive stress772MPa, 64 μm of stress layer depth, impact strength 0.21J.
Embodiment 13
Clean devitrified glass raw sheet is impregnated in 490 DEG C of melting fused salt and keeps the temperature 6h, fused salt by mass percentage,Including sodium nitrate 85%, potassium nitrate 10%, diatomite 3%, antimony oxide 1.7%, cerium oxide 0.3%.After cleaning-drying, thenBe impregnated in 410 DEG C of melting fused salt and keep the temperature 8h, fused salt by mass percentage, including cesium nitrate 65%, rubidium nitrate 29.5%,Diatomite 3%, antimony oxide 2%, cerium oxide 0.5% are dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO248%, Al2O318%, Na2O 12%, K2O 1%, MgO11%, ZrO21.5%, TiO22%, Li2O 5%, ZnO 1.5%, four-point bending intensity 170Mpa, superficial hardness number are637HV, impact strength 0.10J.
Obtained reinforcing devitrified glass four-point bending intensity 667MPa, superficial hardness number 758HV, surface layer value of compressive stress852MPa, 104 μm of stress layer depth, impact strength 0.33J.
Embodiment 14
Clean devitrified glass raw sheet is immersed in 4h in 460 DEG C of melting fused salt, fused salt by mass percentage, includingRubidium nitrate 68%, potassium nitrate 27%, diatomite 2.5%, antimony oxide 2%, cerium oxide 0.5%；It is dry after cleaning, then submergeKeep the temperature 6h in 470 DEG C of melting fused salt, fused salt by mass percentage, including cesium nitrate 89.5%, rubidium nitrate 8%, diatomSoil 1%, antimony oxide 1%, cerium oxide 0.5% are dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO257.5%, Al2O310%, Na2O 8%, K2O 2%, MgO6%, ZrO23%, Li2O 3.5%, TiO23.5%, ZnO 2.5%, P2O54%, four-point bending intensity 224Mpa, surface are hardAngle value is 666HV, impact strength 0.1J.
Obtained reinforcing devitrified glass four-point bending intensity 675MPa, superficial hardness number 758HV, surface layer value of compressive stress845MPa, 101 μm of stress layer depth, impact strength 0.30J.
Embodiment 15
Clean devitrified glass raw sheet is impregnated in 450 DEG C of melting fused salt and keeps the temperature 10h, fused salt is by mass percentageMeter, including potassium nitrate 66%, sodium nitrate 27%, diatomite 3%, antimony oxide 1.5%, potassium pyroantimonate 2%, cerium oxide0.5%；After cleaning it is dry after, then be immersed in 5h in 420 DEG C of melting fused salt, fused salt by mass percentage, including rubidium nitrate89.5%, potassium nitrate 5%, diatomite 3%, antimony oxide 2%, cerium oxide 0.5%；After cleaning-drying, then it is immersed in 480 DEG CMelting fused salt in keep the temperature 8h, fused salt by mass percentage, including cesium nitrate 95.5%, rubidium nitrate 3%, diatomite 1%, oxygenChange cerium 0.5%, it is dry after cleaning.
The ingredient of the devitrified glass raw sheet is SiO248%, Al2O318%, Na2O 12%, K2O 1%, MgO11%, ZrO21.5%, TiO22%, Li2O 5%, ZnO 1.5%, four-point bending intensity 170Mpa, superficial hardness number are637HV, impact strength 0.10J.
Obtained reinforcing devitrified glass four-point bending intensity 676MPa, superficial hardness number 754HV, surface layer value of compressive stress858MPa, 113 μm of stress layer depth, impact strength 0.37J.
Embodiment 16
Clean devitrified glass raw sheet is impregnated in 440 DEG C of melting fused salt and keeps the temperature 12h, fused salt is by mass percentageMeter, including sodium nitrate 70%, potassium nitrate 27%, diatomite 1%, antimony oxide 1.5%, cerium oxide 0.5%；It is done after cleaningIt is dry, then be immersed in 8h in 470 DEG C of melting fused salt, fused salt by mass percentage, including rubidium nitrate 93.5%, potassium nitrate 3%,Diatomite 2%, antimony oxide 1%, cerium oxide 0.5%；It is dry after cleaning, then be immersed in 470 DEG C of melting fused salt and keep the temperature3h, it is dry after cleaning, fused salt by mass percentage, including cesium nitrate 91%, rubidium nitrate 6%, diatomite 0.5%, three oxidationTwo antimony 2%, cerium oxide 0.5%.
The ingredient of the devitrified glass raw sheet is SiO248%, Al2O318%, Na2O 12%, K2O 1%, MgO11%, ZrO21.5%, TiO22%, Li2O 5%, ZnO 1.5%, four-point bending intensity 170Mpa, superficial hardness number are637HV, impact strength 0.10J.
Obtained reinforcing devitrified glass four-point bending intensity 673MPa, superficial hardness number 751HV, surface layer value of compressive stress853MPa, 110 μm of stress layer depth, impact strength 0.35J.