以淀粉为填充剂的碳坯渗硅制备反应烧结碳化硅陶瓷

Preparation of SiC Ceramic by Liquid Silicon Infiltration of Carbonaceous Preform Incorporated with Starch

探索了一条高性能RBSC低成本制造的新途径,本研究以石油焦粉为碳质原料制坯,玉米淀粉为填充剂调整碳坯的密度,纯碳素坯经高温渗硅得到密度为3.12g/cm3,强度为580MPa的反应烧结碳化硅陶瓷.研究结果表明掺加淀粉后素坯中含有更多的微孔,烧结体晶粒平均尺寸为2-4μm,晶粒细化是材料性能比传统RBSC材料高的原因.

The purpose of this study is to explore new methods to prepare reaction bonded silicon carbide(RBSC) materials with high performance in a lower cost. Unlike the traditional RBSC process, a pure carbonaceous preform was made of petroleum coke in which cornstarch was incorporated to adjust the preform carbon density and micropore structure as well. The pure carbonaceous preform was then infiltrated with liquid silicon and the sintered materials has a density of 3.12g/cm(3) and bending strength of 580MPa. The results of observation on the preform microstructure show that. the preform with starch contains more fine pore, which is believe to be vital for complete infiltration. XRD analysis shows that the sintered materials contain beta-SiC and free Si and a little free carbon. SEM shows the average granule size in the sintered materials is about 2similar to4mum and is less than that of the traditional RBSC. We conclude that finer grain is the main cause to the higher strength of the material in comparison with the traditional RBSC.