| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated cemented carbide of which hard coating layer exerts high heat resistance. SOLUTION: The hard coating layer comprising a lower layer a and an upper layer b is physically deposited on a surface of WC based cemented carbide substrate or carbo-nitriding titanium based cermet substrate. The lower layer has an average layer thickness of 0.5 to 5μm, has a composition that is represented by the formula (Ti<SB>1-(</SB>X<SB>+</SB>Y<SB>)</SB>AlXSiY)N and satisfies atomic ratio X: 0.20 to 0.50, Y: 0.15 to 0.30 in the measurement by an Auger spectroscopic analysis device of a central part in the thickness direction, and indicates a texture where amorphous silicon nitride having a skeleton structure (frame structure) surrounds complex nitride particles of hyperfine crystal Ti-Al-Si in the observation by a transmission electron microscope. The upper layer has an average layer thickness of 0.5 to 5μm, has a composition that is represented by the formula (Al<SB>1-</SB>ZSiZ)N and satisfies atomic ratio Z: 0.15 to 0.30 in the measurement by the Auger spectroscopic analysis device, and indicates a texture where amorphous silicon nitride having a skeleton structure surrounds complex nitride particles of hyperfine crystal Al-Si. COPYRIGHT: (C)2003,JPO
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