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Method for preparing dense boron carbide matrix ceramic material by sintering

A boron carbide-based, ceramic material technology, applied in the field of inorganic material preparation, can solve the problems of particle coarsening, densification driving force decline, high manufacturing cost, etc., and achieve the effects of promoting sintering, broad application prospects, and high density

Inactive Publication Date: 2012-10-31
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, on the one hand, hot pressing and hot isostatic pressing can only produce products with relatively small sizes and simple shapes, and on the other hand, the manufacturing costs of hot pressing and hot isostatic pressing are high, thus hindering the application of boron carbide-based ceramic materials.
[0003] Although pressureless sintering (atmospheric pressure sintering) can prepare samples with large size and complex shape, the pressureless sintering of boron carbide ceramics is still a difficult point
The boron carbide ceramics prepared by pressureless sintering have low density, resulting in poor strength, hardness and neutron absorption performance of the ceramics, which has become a bottleneck limiting the application of boron carbide ceramics
[0004] It is believed that one of the reasons hindering the densification of boron carbide ceramics is the boron oxide on the surface of boron carbide powder. The presence of boron oxide will cause the particle coarsening of boron carbide at a lower temperature, resulting in a decrease in the driving force for densification at high temperature.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Mix 40g of boron carbide powder with an average particle size of 300nm, 0.5g of chromium carbide powder with an average particle size of 500nm, 9.5g of titanium boride powder with an average particle size of 1μm, and 40g of alcohol by ball milling for 12h, and dry at 90°C for 12h . Mix powder, 0.5g dispersant, 2.5g monomer MAM (methacrylamide), 0.5g cross-linking agent MBAM (methylenebisacrylamide) and 20g aqueous solution containing soluble starch (the carbon produced by starch is relative to Boron carbide is 3wt%) mixed, after ball milling for 24h, add 1wt% initiator (NH 4 ) 2 S 2 o 8 Solution 0.1g and 1wt% catalyst tetramethylethylenediamine (TEMED) solution 0.1g, after stirring under vacuum for 5min, the slurry was poured into the mold, cured in a constant temperature water bath at 70°C for 2h, and then demolded. After demoulding, dry at 40°C for 12 hours, then at 120°C for 12 hours. After drying, the biscuit is degummed. The debinding temperature is 800°C, an...

Embodiment 2

[0039] After ball milling 35g of boron carbide powder with an average particle size of 0.8μm, 15g of chromium carbide powder with an average particle size of 1μm, 30g of water and 0.5g of dispersant for 48 hours, inject the formed slurry into a plaster mold, and after 24 hours After demolding, the obtained green body was dried at 60°C for 12 hours, and then at 120°C for 12 hours. The dried biscuit is degummed, the heating rate of degumming is 5°C / min, and the degumming temperature is 1000°C. The green body after debinding is subjected to pressureless sintering. The heating rate of pressureless sintering is 15°C / min, the sintering temperature is 2050°C, and the heat preservation is 240min. A boron carbide ceramic with a relative density of about 92% can be obtained.

Embodiment 3

[0041] After mixing 35g of boron carbide powder with an average particle size of 1 μm, 10 g of chromium carbide powder with an average particle size of 2 μm, 5 g of alumina powder with an average particle size of 10 μm, 30 g of alcohol and 0.5 g of dispersant by ball milling for 24 hours, the Dry at 80°C, grind the powder and pass through a 200-mesh sieve. It was formed by dry pressing under 20MPa pressure, then cold isostatic pressing under 200MPa pressure, and dried at 150°C for 48h. The green body is heated to 500°C for debinding, and the heating rate is 20°C / min. Then carry out pressureless sintering, the heating rate is 10°C / min, the sintering temperature is 2100°C, and the heat preservation is 120min. The density of the obtained boron carbide ceramics is about 95%.

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Abstract

The invention relates to a method for preparing a dense boron carbide matrix ceramic material by sintering. The method includes fully mixing boron carbide powders and a sintering aid and subjecting the mixture to forming, drying, binder-removing and sintering to obtain the dense boron carbide matrix ceramic material, wherein the sintering aid at least comprises a first sintering aid which is chromium carbide powders.

Description

technical field [0001] The invention belongs to the field of preparation of inorganic materials, and in particular relates to the technical field of preparation of boron carbide-based ceramic materials, in particular to a method for preparing dense boron carbide-based ceramic materials by sintering. Background technique [0002] The outstanding advantages of boron carbide are low density, high hardness and large neutron absorption cross-section, and it is mainly used in the form of boron carbide ceramic materials. Boron carbide has a low self-diffusion coefficient due to strong covalent bonding and is difficult to sinter. Densification is usually achieved by hot pressing or hot isostatic pressing sintering. However, on the one hand, hot pressing and hot isostatic pressing can only produce products with relatively small sizes and simple shapes. On the other hand, the manufacturing costs of hot pressing and hot isostatic pressing are high, which hinders the application of bor...

Claims

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Application Information

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IPC IPC(8): C04B35/563C04B35/622C04B35/63
Inventor 李晓光江东亮张景贤林庆玲陈忠明黄政仁
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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