The materials or coatings consist of composite grains using a metal core with a chemically bonded sheath. The sheath is pref. obtd. by electroless plating, e.g. in a nickel plating bath contg. alkali-borate and -salts, and/or alkali phosphates. The sheath pref. contains min. 2% B, and/or min.1% P, and possibly other substances, all of which are used to facilitate the subsequent use of the grains. The core is pref. 20-100, esp. 30-70 microns dia., with a sheath 5-50 microns thick; the hardness ratio sheath:core is pref. 1:3. The total compsn. of core plus sheath, by wt., is pref. 5-80% Ni, 0-80% Co, 0-70% Cr, 0.1-10% B, 0-5% Si, 0-15% P, 0-0.5R S, 0-90% W, 0-50% Ti. The composite grains are inexpensive and can be used as coatings or mouldings, e.g. grains with a sheath contg. boron are easily melted to make brazed joints.
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