Abstract: A method of defining valve seats on valve seat supports of an internal combustion engine head. The method includes steps of; (a) roughening the exposed surface of the valve seat support to a finish of 10-50 .mu.m RA; (b) thermally spraying a stream of composite particles onto the roughened support surface, using gaseous propellants with sufficient heat and force to produce a dense adherent composite coating of metal and metal oxide particles and to a thickness no greater than 1-1.5 mm; and (c) finish machining if necessary, the sprayed coating to define the valve seat surface. The composite coated product consists of a metal/metal oxide mixture that possesses one or more of the following characteristics: a surface porosity of 2-5%, a density of 6.5-8 grams/cc, a Vickers hardness of about 280 kg/mm.sup.2 at 450.degree. C., high wear resistance and high corrosion resistance.

Abstract: Method of making seat inserts by thermally spraying bulk material. The method includes the steps of: (i) preparing a mandrel having an outside dimension not greater than the desired inside dimension of the desired insert, the mandrel having a part to provide for separation of the sprayed bulk material from the mandrel, (ii) thermal spraying separate particles of one or more types of steel or nickel alloys in the presence of a controlled oxidizing medium to form a bulk composite material on the mandrel with a density of at least 99% and, (iii) after cooling the bulk material, removing such material from the mandrel and slicing it into discrete seat shapes for implanting into the final product.