Cubic boron nitride cutting tool

Year	Description
1997	Invention patented by Michael Thysell and Torbjorn Selinder on December 17th, 1997. Abstract: A multilayer coated cutting tool comprising a cemented carbide body with at least one sintered-on inlay containing polycrystalline cubic boron nitride forming at least one cutting edge. Reduced crater wear of the rake face of the tool is achieved by reducing chemical interaction between tool and workpiece/chip material, and used edges of indexable inserts can be readily identified. The tool is provided with a multilayer coating by thermal CVD, the coating including (1) a first, innermost, layer of TiC.sub.x N.sub.y O.sub.z with x+y+z=1, with y>x and z<0.2, with equiaxed grains with size <0.5 .mu.m and a total thickness <1.5 .mu.m, (2) a second layer of TiC.sub.x N.sub.y O.sub.z with x+y+z=1, preferably with z=0, x>0.3, most preferably x>0.5, having a thickness of 1-8 .mu.m, with columnar grains, and (3) a third layer of a smooth, fine-grained (grain size about 1 .mu.m) layer of (.alpha.-Al.sub.2 O.sub.3 or .kappa.-Al.sub.2 O.sub.3 or mixtures thereof, with a thickness of 2-10 .mu.m.
Source: selected by the editor from original sources.

Invention: Cubic boron nitride cutting tool