| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface coated cutting tool whose hard coating layer can exert an excellent resistance against chipping in a high-speed intermittent cutting. SOLUTION: By means of evaporative deposition process, the surface of a tool base is fitted with a hard coating layer whose underlayer (a) is configured with Ti compounds and overlayer (b) consists in a two-phase mixed oxide layer including Al<SB>2</SB>O<SB>3</SB>phase and ZrO<SB>2</SB>phase in the condition evaporated with chemical vapor deposition, wherein the Zr/(Al+Zr) value (by atomic ratio) of the layer ranges between 0.003-0.2, and the crystal grains constituting the layer assume a grain boundary surface orientation where the grain boundary surface unit with the mutually crossing angle of the normals to the (0001) plane on the boundary surface of the adjoining crystal grains with each other and the one of the normals to the (10-10) plane being 15 degrees or less occupies 30% or more of the whole grain boundary surface unit. COPYRIGHT: (C)2008,JPO&INPIT
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