Ngk Spark Plug Company, Limited

Fumihiro Kikkawa

Ryoji Toyoda

Atsushi Komura

Shota Nozaki

To improve the adhesion resistance and wear resistance of a surface-coated cutting tool. The surface-coated cutting tool includes a tool substrate, and a single-component coating layer composed of a composite nitride of Cr (chromium), Al (aluminum), and V (vanadium) and disposed on the surface of the tool substrate. The composite nitride is characterized by being represented by a compositional formula: CrAlVN satisfying the following relations:0.11&#x2264;&#x2264;0.26;0.73&#x2264;&#x2264;0.85;0&#x3c;&#x2264;0.04; and&#x2264;1(wherein a, b, and c each represent an atomic proportion). The single-component coating layer has both a hexagonal phase and a cubic phase.

Surface-coated cutting tool

A sialon sintered body and a cutting insert each having thermal shock resistance and VB wear resistance. The sialon sintered body and the cutting insert contain &#x3b2;-sialon and 21R-sialon and exhibit an X-ray diffraction peak intensity ratio [(I/I)&#xd7;100] of 5% or greater and smaller than 30%, wherein Irepresents the sum of the peak intensities of the sialon species, and Irepresents the peak intensity of 21R-sialon, the ratio being calculated from the peak intensities of the sialon species obtained by using X-ray diffractometry.

Sialon sintered body and cutting insert

A sialon sintered body includes a &#x3b2;-sialon (SiAlON) and at least one polytype sialon, wherein a Z value is 0.4 or greater and 1.0 or less, a proportion of a total of peak intensities of each polytype sialon to a total of peak intensities of each sialon, is 10% or greater and 50% or less, at least one rare earth element B selected from a group consisting of La and Ce and at least one rare earth element C selected from a group consisting of Y, Nd, Sm, Eu, Gd, Dy, Er, Yb, and Lu is included, a molar ratio of the rare earth element B and the rare earth element C is 1.0:0.06 to 1.0:3.5 in terms of an oxide, and a total content of the rare earth elements B and C is 0.8 mol % or greater and 4.0 mol % or less in terms of an oxide.

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Inazawa, Japan

Fumihiro Kikkawa