| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface coated cermet-made cutting tool including a hard coating layer exhibiting excellent chipping resistance in cutting difficult-to-cut material. SOLUTION: In this surface coated cermet-made cutting tool, the hard coating layer is formed on the surface of a tool base. The hard coating layer includes: a lower layer formed of Ti compound layer 3 to 20μm; an inter-layer contact layer formed of a contactα-type Al<SB>2</SB>O<SB>3</SB>layer 0.1 to 1.9μm; and an upper layer formed of a reformedα-type Al<SB>2</SB>O<SB>3</SB>layer 6 to 20μm. The above upper layer and the inter-layer contact layer are formed ofα-type Al<SB>2</SB>O<SB>3</SB>layer. In the case of measuring an angle of inclination made by a normal of (0001) face, which is a crystal plane of a crystal grain, using a field emission type scanning electron microscope to create an inclination angle frequency distribution graph, theα-type Al<SB>2</SB>O<SB>3</SB>layer shows an inclination angle frequency distribution graph in which the highest peak exists in an inclination angle section within the ranges of 30 to 45 degrees and 75 to 90 degrees, and the total of frequencies existing in the inclination angle sections occupies 50% or more of the whole frequency, and also the surface roughness of the reformedα-type Al<SB>2</SB>O<SB>3</SB>layer is set to Ra:0.2μm or less. COPYRIGHT: (C)2007,JPO&INPIT
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