Non-pyrophoric submicron alloy powders of group viii metals

Abstract

Metal products herein are essentially submicron alloy powders of Group VIII base and Group VIII noble metals having non-pyrophoric and magnetic properties. One such product is prepared with isomorphous compounds of nickel and palladium, in a quantitative weight ratio of at least 99% of the former and 1% or less of the latter. The palladium is homogenously dispersed in the product nickel structure sites. An aqueous chemical process involving spontaneous nucleation is employed in the manufacture of the alloy product. In preferred form, small concentrations of palladium and/or platinum ions are added to ionic nickel and/or cobalt solutions. The ratio of nickel and/or cobalt ions to palladium and/or platinum ions is critical. A hot solution of the metal ions of nickel and/or cobalt and palladium and/or platinum is mixed with hydrazine in a hot basic aqueous solution, and rapidly diluted with hot water. The precipitate formed is filtered, sequentially chemically washed and dried. The dried alloy product is a black, non-pyrophoric, magnetic powder. Examination by electron probe and X-ray diffraction shows the alloy product to be a solid solution of the constituent metals. Scanning electron microscopy and BET surface area measurement establishes that the ultimate particles are submicron.