Process for making a modified silicon aluminum oxynitride based composite cutting tool

Claim 1

A process for obtaining an abrasion resistant cutting tool having a hard refractory material distributed in a homogeneous matrix containing a modified silicon aluminum oxynitride comprising: mixing from about 20 to about 90 volume percent silicon nitride, from about 5 to about 60 volume percent aluminum oxide, and from about 20 to about 25 volume percent of a modifier to form a mixture; reacting said mixture at a temperature from about 1400° C. to about 1800° C. for a period of time from about one to about eight hours in a non-oxidizing atmosphere to form a reacted mixture; comminuting a blend comprising from about 40 to about 95 volume percent of said reacted mixture and from about 5 to about 60 volume percent of a hard refractory material to form a composite blend; and densifying said composite blend to form a homogeneous matrix of said reacted mixture having a dispersed phase of said hard refractory material throughout said homogeneous matrix, said densifying being sufficient to obtain a density greater than 98 percent of theoretical density of said composite blend.