| 摘要 |
PURPOSE:To produce excellent Co-W coated WC powder for powder metallurgy by subjecting the WC powder to an activation treatment and immersing the same into an electroless cobalt plating bath contg. tungstate and hydrazine compd. CONSTITUTION:The WC powder (about 0.1-50mu average grain size) is treated with, for example, an SnCl2-PdCl2 activating soln. by which the surface thereof is activated. The activated WC powder is immersed into the electroless cobalt plating bath contg. the tungstate (sodium tungstate, etc.) and hydrazine compd. (hydrazine hydrochloride, etc.). Cobalt chloride, etc., are used for the cobalt plating bath and the concn. of the cobalt is made about 0.02-0.4mol/l. The concn. of the tungsten is made usually about 0.001-0.6mol/l. The Co-W alloy is thereby precipitated in the form of a uniform layer on the surface of the WC powder and the excellent coating is formed without forming dendrite.
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