CUTTING TOOL HAVING BODY COATED BY HARD WEAR RESISTANT FILM

摘要

PROBLEM TO BE SOLVED: To provide a coated cutting tool for chip forming containing at least one layer of an alumina (Al2O3) which is formed by a film featured by fine equiaxed grain. SOLUTION: A body is provided which substantially consists ofα-Al2O3at least in one layer and keeps at least partially coated with one or a plurality of heat resistant layers. The layer of Al2O3is formed of substantially equiaxed grain having an average grain size of 1μm or less, and has bimodal grain size distribution consisting of coarse grains having an average grain size of 0.5 to 1μm and fine grains having an average grain size of up to 0.5μm. A layer of Al2O3contains a groove-form region containing titanium (at least 5 at.%) but containing neither nitrogen nor carbon. The special microscopic texture is achieved by temporarily stopping gas necessary for growth of a layer of Al2O3, and by introducing TiCl4. COPYRIGHT: (C)2008,JPO&INPIT