Abstract: In its broadest aspects, the present invention is directed to a method for improving the abrasion resistance of the annular interior surface of an annulus. Such method comprises the steps of (a) placing said annulus heated to an elevated CVD diamond-forming temperature in a vacuum chamber held under reduced pressure; (b) providing a hydrocarbon/hydrogen gaseous mixture within said chamber; (c) at least partially decomposing said gaseous mixture in said chamber; and (d) directing said at least partially decomposed gaseous mixture into said heated annular interior for diamond deposition/growth to occur on said annular interior surface. As noted above, spray nozzles, valves, injectors, wire drawing dies, and like annular products are ideally suited for use in accordance with the precepts of the present invention.

Abstract: A Si--SiC ceramic layer is bonded to a non-porous SiC substrate with the Si etched from the layer to form a relatively porous surface on the otherwise non-porous high strength SiC substrate. A quartz layer is softened by heating and forced into the pores of the porous layer to form a mechanical bond to the SiC substrate. A refractory metal layer is bonded to the quartz layer to complete the joint. A refractory metal support component is then bonded to the refractory layer whereby the quartz serves as a high strength, high temperature reaction barrier between the metal of the refractory layer and the silicon of the SiC substrate.

Abstract: An improved thermal barrier coating is disclosed. The coating is formed on a metal part to be exposed to high temperature gases. The metal part is first coated with an adherent sublayer of MCrAlY alloy. In this case, the M of the MCrAlY is nickel, cobalt, iron, or some combination of these metals. A diffused layer of MCrAlY combined with a low concentration of mullite is formed over the MCrAlY subcoating and the mullite is increased in concentration as the thickness of the layer increases. The outer surface of the layer is all mullite. Improved life expectancy and decreased thermal conductivity is achieved.

Abstract: A Si--SiC ceramic layer is bonded to a non-porous SiC substrate with the Si etched from the layer to form a relatively porous surface on the otherwise non-porous high strength SiC substrate. A quartz layer is softened by heating and forced into the pores of the porous layer to form a mechanical bond to the SiC substrate. A refractory metal layer is bonded to the quartz layer to complete the joint. A refractory metal support component is then bonded to the refractory layer whereby the quartz serves as a high strength, high temperature reaction barrier between the metal of the refractory layer and the silicon of the SiC substrate.

Abstract: A method of embedding an oxidation resistant abrasive material in the tip of a turbine blade is taught. The oxidation resistant abrasive may be aluminum oxide. Its low density is increased by coating fine particles with platinum metal to achieve a density greater than that of the metal of the blade tip. The blade tip is then melted locally to provide a pool of melt into which the high density aluminum oxide can be inserted. Freezing the melt embeds the aluminum oxide in the blade tip.

Abstract: A method is provided for making silicon-based ceramic composites having reduced tendency to form complex silicides when in contact with high performance metals or metallic alloys at elevated temperatures. The surface of the silicon-based ceramic composite, such as silicon carbide-silicon matrix composite, is etched, treated with an inorganic oxide mixture and fired. Improved performance is provided when the resulting composite is used in a specific application in contact with a high performance metal or metallic alloy, such as a gas turbine bucket.