Fabrication of Highly Dense Silicon Nitride Ceramics Without Additives by High Pressure Sintering

摘要

Silicon nitride (Si3N4) is one of candidate materials for the engineering ceramics which is used at high temperatures. The mechanical strengths of hot pressed or sintered Si3N4 ceramics containing some amount of additives, however, are deteriorated at elevated temperatures. To improve the high temperature strength of Si3N4 ceramics, an attempt to consolidate Si3N4 without additives was made by high pressure sintering technique. Scanning electron micrographs of fracture surfaces of the sintered bodies showed the bodies had finely grained and fully self-bonded sintered bodies were 310N sq m at room temperature and 174N/sq m at 1200 C.