Silicon carbide based reinforced composite ceramic and preparation

Abstract

The invention discloses a reinforced silicon carbide-based composite ceramic and a preparation method thereof. The composite ceramic is characterized by comprising the following components based on weight percentages: 30%-40% of silicon carbide powder, 5%-17% of boron carbide powder, 9%-12% of nano carbon black and 40%-50% of silicon metal. The method comprises the following steps: firstly, ball milling and wet mixing are performed on the silicon carbide powder, the carbon black and the boron carbide powder to obtain mixed powder, and a bonding agent PVB is added for granulation, die pressing is performed for forming; then the formed green compact is dried and put in an air furnace for binder removal; and finally, the obtained green compact is put into a graphite crucible with silicon powder, and siliconizing and sintering are completed after 1-3h heat preservation at 1450-1550 DEG C under a vacuum environment, thus obtaining a sintering body. The boron carbide particle reinforced reaction sintered silicon carbide composite ceramic prepared by the method can be widely used as a structural material under high-temperature atmosphere and corrosive atmosphere, a frictional wear material and the like; and as the composite ceramic has better obdurability and hardness, the ceramic can be used as a substitute material of the traditional reaction sintered silicon carbide.

Description

technical field [0001] The invention relates to a composite ceramic and a preparation method thereof, in particular to a silicon carbide-based reinforced composite ceramic and a preparation method thereof. Background technique [0002] Silicon carbide has excellent high temperature strength, chemical stability, high hardness, good thermal shock resistance and low thermal expansion coefficient, so it is widely used in metallurgy, chemical industry, aerospace and thermal engine and other fields. The reaction sintered silicon carbide (RBSC) material prepared by the reaction sintering process has most of the advantages of silicon carbide ceramics, but the presence of free silicon reduces the strength and service temperature of the material, and the relatively low toughness also limits the wide application of RBSC materials. . At present, the common methods of improving RBSC are as follows: [0003] 1) Alloy infiltration and metal toughening method. After the RBSC material is p...

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Problems solved by technology

However, the sintering temperature reaches 1750°C, which will cause the volatilization of boron on the surface of the sintered body and reduce the surface properties of the material.

Moreover, the product obtained by gel injection molding has a large porosity and a high amount of residual silicon, which reduces the performance of the material at high temperature.

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