| 摘要 |
PROBLEM TO BE SOLVED: To obtain a highly touch ceramic, especially a silicon nitride composite material hardly being destroyed, by dispersing Ce6 Si6 N8 O9 polycrystal to be subjected to martensitic transformation into silicon nitride. SOLUTION: A method for mixing CeO2 with Si3 N4 , reacting the compounds in a nonoxidizing atmosphere at 1,500-1,900 deg.C for 0.02 to 15 hours to synthesize Ce6 Si6 N8 O9 polycrystal to be subjected to martensitic transformation, then grinding the compound, mixing 7-30wt.% of the ground compound with 93-70wt.% of silicon nitride and baking the mixture in a nonoxidizing atmosphere at 1,550-1,800 deg.C for 0.02-5 hours may be cited as a method for advantageously producing the composite material. Preferably, the surface of the highly tough silicon nitride composite material is polished by a polishing machine for 3-60 minutes to form a twin crystal on the surface layer. |
