Gel casing preparation method of reaction-sintered boron carbide ceramic composite material

A gel injection molding, boron carbide ceramic technology, applied in the field of ceramics, can solve the problems of powder agglomeration, uneven distribution, unstable product performance, etc., to achieve improved mechanical properties, wide application fields, flexural strength and fracture resistance The effect of improving toughness

Active Publication Date: 2016-07-20
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, it is difficult to completely eliminate the "bridge arch effect" between powders during the molding process, and the uneven distribution of carbon source and molding pressure may easily cause powder agglomeration, so the structure uniformity of the green body is poor, which leads to the distribution of the phases in the sintered body Inhomogeneity, resulting in unstable performance of the product

Method used

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  • Gel casing preparation method of reaction-sintered boron carbide ceramic composite material
  • Gel casing preparation method of reaction-sintered boron carbide ceramic composite material
  • Gel casing preparation method of reaction-sintered boron carbide ceramic composite material

Examples

Experimental program
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Effect test

Embodiment 1

[0043] A preparation method for gel injection molding of a reaction sintered boron carbide ceramic composite material, comprising the following steps:

[0044] Step 1: Mix resorcinol (R), formaldehyde (F), sodium carbonate (N) and deionized water (W), stir until completely dissolved, add B with an average particle size of 3.5 μm 4 C powder, ball milled and mixed evenly to form B 4 C mixed slurry; wherein, by molar ratio, R / F=0.5, R / N=500, R / W=0.05; B 4 The content of boron carbide in C mixed slurry is 55wt%;

[0045] Step 2:

[0046] (1) will B 4 The mixed slurry of C, vacuum degassing and injection mold sealing;

[0047] (2) will seal the B 4 Put the mixed slurry of C into a water bath at 70°C for sol-gelation, and continue aging at the same temperature for 12 hours after forming a gel to obtain resorcinol-formaldehyde (RF) polymer / B 4 C hydrogel, wherein, after the resorcinol-formaldehyde (RF) polymer is carbonized, the residual carbon rate is 60wt%;

[0048] (3) After ...

Embodiment 2

[0054] A preparation method for gel injection molding of a reaction sintered boron carbide ceramic composite material, comprising the following steps:

[0055] Step 1: Mix resorcinol (R), formaldehyde (F), sodium carbonate (N) and deionized water (W), stir until completely dissolved, add B with an average particle size of 3.5 μm 4 C powder, ball milled and mixed evenly to form B 4 C mixed slurry; wherein, by molar ratio, R / F=0.5, R / N=50, R / W=0.01; B 4 The content of boron carbide in C mixed slurry is 45wt%;

[0056] Step 2:

[0057] (1) will B 4 The mixed slurry of C, vacuum degassing and injection mold sealing;

[0058] (2) will seal the B 4 Put the mixed slurry of C into a 95°C water bath for sol-gelation, and then continue to age at the same temperature for 12 hours after forming a gel to obtain resorcinol-formaldehyde (RF) polymer / B 4 C hydrogel, wherein, after the resorcinol-formaldehyde (RF) polymer is carbonized, the residual carbon rate is 60wt%;

[0059] (3) Af...

Embodiment 3

[0065] A preparation method for gel injection molding of a reaction sintered boron carbide ceramic composite material, comprising the following steps:

[0066] Step 1: Mix resorcinol (R), formaldehyde (F), sodium carbonate (N) and deionized water (W), stir until completely dissolved, add B with an average particle size of 3.5 μm 4 C powder, ball milled and mixed evenly to form B 4 C mixed slurry; wherein, in molar ratio, R / F=0.5, R / N=50, R / W=0.08; B 4 The content of boron carbide in C mixed slurry is 60wt%;

[0067] Step 2:

[0068] (1) will B 4 The mixed slurry of C, vacuum degassing and injection mold sealing;

[0069] (2) will seal the B 4 Put the mixed slurry of C into a water bath at 80°C for sol-gelation, and continue to age at the same temperature for 4 hours after forming a gel to obtain resorcinol-formaldehyde (RF) polymer / B 4 C hydrogel, wherein, after the resorcinol-formaldehyde (RF) polymer is carbonized, the residual carbon rate is 60wt%;

[0070] (3) After...

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Abstract

A gel casing preparation method of reaction-sintered boron carbide ceramic composite material includes the steps of firstly, mixing resorcinol, formaldehyde and sodium carbonate with deionized water, and adding B4C powder to form B4C mixed slurry; secondly, performing vacuum degassing and injection molding sealing on the mixed slurry; performing sol gelation in water bath, and aging for 4-50 hours; drying under normal pressure, and performing high-temperature carbonization to obtain a B4C/C biscuit; thirdly, placing silicon on the B4C/C biscuit, performing high-temperature infiltration to obtain a sintered body, and cooling to remove redundant silicone to obtain the reaction-sintered boron carbide ceramic composite material. The method has the advantages that the mesoporous carbon is introduced during the formation of the biscuit, and the B4C/C biscuit with an even structure and a controllable hole structure is obtained; the strength of the B4C/C biscuit is 10-50MPa, machining is facilitated, and the B4C/C biscuit can be used for preparing products of complex shapes; the Vickers hardness of the reaction-sintered boron carbide ceramic composite material is 17-26GPa, the bending strength of the reaction-sintered boron carbide ceramic composite material is 255-484MPa, and the fracture toughness of the reaction-sintered boron carbide ceramic composite material is 3-5MPa.m<1/2>.

Description

technical field [0001] The invention belongs to the technical field of ceramics, and in particular relates to a gel injection molding preparation method of a reaction sintered boron carbide ceramic composite material. Background technique [0002] Boron carbide is an important superhard material whose hardness is second only to diamond and cubic boron nitride in nature. It has the advantages of high hardness, low density, high modulus, high temperature semiconductor characteristics, good thermal stability and corrosion resistance, etc. It is A high-performance engineering ceramic material is used as liquid-gas sealing material, aerospace engine nozzle, bulletproof armor material, semiconductor precision structural parts, etc., and is widely used in national defense, machinery, chemical industry, aerospace and other fields. However, its two fatal shortcomings of difficult sintering and low fracture toughness have greatly restricted the application of boron carbide ceramic mat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/563C04B35/622C04B35/624C04B35/634C04B35/65
CPCC04B35/563C04B35/622C04B35/624C04B35/63476C04B35/65C04B2235/3826C04B2235/6023C04B2235/96
Inventor 茹红强徐昱峰王伟常龙飞张鑫姜岩叶超超张美云
Owner NORTHEASTERN UNIV
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