Silicon nitride powders were prepared using the sol-gel method followed by the carbothermal reduction. MTMS, PTMS, and PTMS-TMOS were taken a reaction with distilled water and ammonia solution. By this reaction the various silanes hydrolyzed and condensed as precursor gel powders. These gel powders were heat-treated in a nitrogen gas flow at 1350-1500℃. The unhydrolyzed alkyl(methyl or phenyl) groups contained in the gel powders played the roles of a reducing agent for the carbothermal reduction.
Reaction temperature, raw silanes and the characteristics of the gel powders affected the final properties of silicon nitride powders. The gel powders synthesized from MTMS and PTMS silanes did not form silicon nitride powders by the carbothermal reduction. In the PTMS-TMOS. system, however, alpha silicon nitride powders developed very well.
