Alumina-based mixed ceramic for cutting tools - contains titanium and tungsten carbide(s) or carbonitride(s)

摘要

A novel Al2O3-based mixed ceramic contains 0-5 wt.% ZrO2 and 20-50 wt.% hard material which consists of metal carbides and carbonitrides and which has the formula TiW(C,N). The Al2O3 particles have a mean particle size of max. 0.5 microns and the hard material particles have a mean particle size of max. 0.4 microns. Also claimed is a method of producing an Al2O3-based mixed ceramic by: (a) finely grinding and mixing 20-50 wt.% of a mixt. of titanium carbide or carbonitride (specific surface greater than 10 m2/g.) and 5-10% (by wt. of the Ti component) tungsten carbide (mean particle size much less than 0.4 microns) with 50-80 wt.% of fine grained Al2O3 powder, opt. with addn. of up to 5 wt.% zirconium oxide and/or up to 0.5 wt.% sintering aid, in an organic medium or water in an attrition ball mill and adding a temporary organic binder; (b) eliminating the grinding liq. and sieving the dry powder mixt. through a 250 micron sieve; and (c) uniaxially or isostatically hot pressing the powder mixt. in a mould according to a predetermined pressure and temp. cycle. Further claimed is an Al2O3-based mixed ceramic produced by the above method.