Ceramic-based substrate for coating diamond and method for preparing substrate for coating
AssigneeNgk Spark Plug Co., Ltd.
InventorsSatoshi Iio, Takahisa Ushida, Takashi Okamura, Masakazu Watanabe
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Abstract
Ceramic-based substrate for coating, e.g., diamond has a basic irregularities surface having a surface roughness Rz of 2 to 20 .mu.m, with Rz at angle regions of 40% or more of that for other than the angle regions. The basic irregularities surface has micro-sized irregularities on an order of crystal grains constituting the uppermost surface (0.5 to 10 .mu.m), forming dual irregularities surface structure. Coating layer engages with surface irregularities to secure firm adhesion at the cutting edge. WC-based cemented carbide is used as substrate and N-containing surface layer is formed by heat treatment to form the surface irregularities.
Claims14
A method for producing a substrate for coating comprising
- (a) providing a WC-based cemented carbide piece mainly composed of WC,
- (b) heat-treating said cemented carbide piece at a temperature not lower than a temperature at which a liquid phase of said WC-based cemented carbide piece is generated and not higher than its sintering temperature under a normal-pressure atmosphere containing a N2 gas of 0.05 to 5 vol %, preferably 0.5 to 3 vol %,
- (c) forming a N-containing surface layer presenting surface irregularities on a surface of said WC-based cemented carbide piece.
A method for producing a substrate for coating comprising
- (a) providing an angle region of a WC-based cemented carbide piece, mainly composed of WC, with a rounded profile in which a profile line on the cross-section of the angle region comprises a curve having a radius of curvature R of not less than 0.005 mm,
- (b) heat-treating the WC-based cemented carbide piece from the step (a) at a temperature not lower than a temperature of generating a liquid phase of said WC-based cemented carbide and lower than its sintering temperature, under a normal-pressure atmosphere containing 0.05 to 5 vol %, preferably 0.5 to 3 vol %, of a N2 gas, and
- (c) forming a N-containing surface layer presenting surface irregularities on a surface of said WC-based cemented carbide piece.
Dependencies are inferred from the claim text.