Silicon nitride-cubic boron nitride composite material used as a cutting ceramic or a substrate for coatings

摘要

A high density silicon nitride-cubic boron nitride composite material, having specified cubic boron nitride and sintering aid contents. The silicon nitride composite material contains up to 50 (preferably 0.5-15) wt.% cubic boron nitride and up to 10 (preferably 1.3-4) vol. % sintering aid and has greater than 97% theoretical density. An Independent claim is also included for production of the above composite material by wet ball milling the raw materials with organic fluidizer addition to increase the specific surface, adding an organic binder, drying, granulating, sieving, dry pressing to green bodies and densifying to final density by encapsulated hot isostatic pressing. Preferred Features: The sintering aid comprises one or more high melting rare earth metal oxides