SURFACE-COATED CUTTING TOOL EXHIBITING EXCELLENT LUBRICITY, CHIPPING RESISTANCE AND WEAR RESISTANCE DURING HIGH-SPEED INTERMITTENT CUTTING

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool with a hard coated layer exhibiting excellent lubricity, chipping resistance and wear resistance during high-speed intermittent cutting of a Ti alloy or stainless steel, etc.SOLUTION: A surface-coated cutting tool includes an aluminum oxide layer having average layer thickness of 0.2-5 μm and high smoothness on a surface of a tool base body including a hard layer on the surface. The aluminum oxide layer is formed of a substrate and spheroidized structures dispersed in the substrate. The substrate is formed of an amorphous phase of aluminum oxide. The spheroidized structures are formed of an aggregate of an amorphous phase, an acicular crystal phase and a planar crystal phase. An area ratio occupied by the spheroidized structures contained in a vertical cross section of the aluminum oxide layer is 20-60 area%, and the radius of an approximate circle is 0.02-0.5 μm. Chlorine of 1.0-10 atomic% is contained in the aluminum oxide layer substrate.