| 摘要 |
PURPOSE:To permit easy production of secure sintered hard alloy products having a high true density by coating the surface of a sintered hard alloy with metals having high affinity and kneading the alloy with a binder, then molding the mixture to a prescribed shape and sintering the molding after a treatment to remove the binder. CONSTITUTION:The sintered hard alloy 2 such as WC is melted and the powder 3 having <=100mum is formed by a water atomization method A, etc. The metals such as Ni, Al, Co, Cr, and others having high affinity are coated on the surface thereof to 100Angstrom -several mm thickness by a method such as PVD or CVD. A prescribed amt. of the binder 8 such as olefin resin is added and kneaded to and with the metal coated powder 6 to form molding powder 9 which is molded by an injection molding machine 12 to the molding 11 having a desired shape; thereafter, the molding is heated to about 400 deg.C in a heating furnace 14 to evaporate away the binder. The molding 16 subjected to the removal of the binder is put into a vacuum furnace or inert gaseous atmosphere furnace 17 where the molding is imposed on a table 19 of an ultrahigh- frequency oscillator 18 and is sintered at 1,430 deg.C. The sintered hard alloy products which have the compsn. consisting of 53-92% WC, 3-11% Co as a bond phase and 4-13% C and obviate chipping during working as a grinding tool are obtd.
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