纯碳坯渗硅制备反应烧结碳化硅的研究

Research on the Sintering of Reaction Bonded Silicon Carbide with Pure Carbonaceous Preform

以石油焦粉制备纯碳素坯高温渗硅的方法制备了反应烧结碳化硅陶瓷。研究表明 ,素坯的碳含量 (或孔隙率 )对材料的最终物相组成有决定性的影响 ;合成 Si C时的热效应以及反应过程中的体积效应 ,是影响石油焦坯体烧结的根本原因 ;烧结时间短使晶粒细化 ,是材料强度提高的主要原因。 90 %理论碳含量的素坯渗硅后 ,所得材料的密度为 3.0 8～ 3.12 g/ cm3,强度为 (5 5 0± 30 )

Reaction bonded silicon carbide (RBSC) ceramics was prepared by infiltrating the pure carbonaceous preform in which petroleum coke was used as raw material. The results show that carbon content in the preform is vital to the phase composition of the final RBSC materials. The heat effect and the volume effect in the reaction process are the main factors influencing the sintering of petroleum coke preform. Shorter sintering time results in finer grain size, which is the main cause for higher materials flexural strength. Materials made from preforms with 90 percent of the theoritical carbon content have a density of (3.10±0.02) g/cm 3 and a flexural strength of (580±30) MPa.