| 摘要 |
PROBLEM TO BE SOLVED: To suppress the influence of the occurrence of recessed and projection parts due to the wear of a bond layer by arranging ultra-abrasive grains densely and continuously on a surface of a hard raw material in the hard raw material used as a material of a part for which abrasion resistance of tools is demanded. SOLUTION: In a hard raw material made of ultra-abrasive grains such as diamond and CBN and matrix bond 4, ultra-abrasive grains having a blending ratio of 55 to 75 volume % of coarse grains 1 having particle diameter of 20 to 30μm, 15 to 25 volume % of medium grains 2 having particle diameter of 8 to 12μm, and 10 to 20 volume % of fine grains 3 having particle diameter of 2 to 3μm and mixed with the matrix bond 4 made of a brazing filler metal containing active metal or self-melting alloy, are heated, are pressurized, and are sintered to obtain the hard raw material having a structure in which ultra- abrasive grains are continuously and densely arranged on a surface 5 thereof.
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