| 摘要 |
PURPOSE:To reduce deformation of the ceramics sintered body by applying the surface of a molded body with the mixed powder consisting of Si3N4, BN and a sintering adjuvant and sintering the molded body in a N2 atmosphere of normal pressure or pressurization. CONSTITUTION:After adding and mixing the proper amount of a sintering adjuvant selected from among MgO, Al2O3 and Y2O3, etc., and water with Si3N4 powder, the mixture is dried and the dry powder is molded into a required shape. The molded body having a volume of at least 5 % for a vessel is placed on a floor plate made of an Si3N4-based ceramics sintered body and introduced into a heat resistant vessel such as a cover-fitted crucible made of carbon and covered and then inserted into a sintering furnace in a practically closed state. Thereafter the molded body is roasted for a prescribed time at 1700-1900 deg.C in the N2 atmosphere of normal pressure or at 1800-200 deg.C in a pressurized N2 atmosphere of 0.5-10 MPa. Thereby an Si3N4-based ceramics sintered body is obtained which is little in deformation and has a high density. |
