Abstract: Sintered composite abrasive material useful in abrasives (grinding wheels, abrasive discs and paper, etc.) and cutting tools, comprising an .alpha.-Al.sub.2 O.sub.3 matrix of sub-micron crystallite size made by sol-gel processing with a dispersed phase therein of mechanically resistant material, preferably essentially isotropic grains, added directly to the sol or gel stage of matrix formation.

Abstract: Fluorine content of tantalum and niobium hydroxides is reduced to under 0.5 weight % by washing such hydroxide precipitates (as obtained by HF digestion and solvent extraction) with dilute ammonia (1 to 10%) and then water in two washing stages. The first washing stage includes a partial neutralization and the used wash water of the second stage is advantageously recycled, after adjustment of its ammonia concentration, for use as the first stage washing liquid.

Abstract: MCrAlY composite material with platinum and/or rhodium alloying elements as 5-15 wt. % thereof and containing included particles of carbides vanadium, niobium, tantalum, titanium, zirconium, hafnium, chromium, molybdenum and/or tungsten and/or mixtures thereof, enhancing the corrosion- and wear-resistance of such materials at high temperatures.

Abstract: In an advantageous process for producing powdered aluminium alloys which have a catalytic action or are capable of acting as precursors of catalysts, good results are obtained if the alloy is atomized with water and/or a gas at a temperature of 50.degree. to 500.degree. C. above its melting point and then cooled and dried.

Abstract: A molybdenum metal powder having an outer shell coating of MoO.sub.2 is useful in flame spray or plasma spray processes and is prepared by partially oxidizing molybdenum powder in a carbon dioxide atmosphere at temperatures of up to 1200.degree. C.

Abstract: Metal powder agglomerates of individual particles comprising (i) more than 70% by weight of one or more metals selected from the group consisting of the elements molybdenum, rhenium and tungsten and (ii) one or more binder metals selected from the group consisting of iron, cobalt, nickel, copper, silver, gold, palladium, platinum, rhodium, chromium and rhenium, wherein the individual particles have grain sizes of less than 2 .mu.m and all the metal particles lie side by side in uniform random distribution are useful as the powder required for producing shaped, sintered articles in a powder metallurgical preparation.