Abstract: A new family of chromium boride coatings having excellent adhesive wear and corrosion resistance is disclosed. The coatings comprise hard, ultrafine, chromium boride particles dispersed in a metal matrix, the particles having an average particle size of less than one micron and constituting less than about 30 volume percent of the coating, the balance being metal matrix. The metal matrix may be composed of nickel or a nickel base alloy containing a metal selected from the group consisting of chromium, silicon and iron. The coatings may be prepared by a process which comprises depositing a mechanically blended powder mixture of chromium metal or a chromium alloy or mixture of both, and a boron-containing alloy onto a substrate and then heat treating the as-deposited coating. The heat treatment effects a diffusion reaction between the deposited elements resulting in the formation of ultrafine particles of chromium boride dispersed in a metal matrix.

Abstract: A TiB.sub.2 -M coating which consists of greater than 50 vol % TiB.sub.2 hard phase particles in a metal or metal alloy (M) matrix that is produced by a thermal spray process using sintered TiB.sub.2 -M powders. The TiB.sub.2 -M powders were fabricated by sintering TiB.sub.2 powders and elemental metals or metal alloys which were selected to form a desired matrix for the TiB.sub.2 particles.

Abstract: A duplex coating and method for making same wherein a primary layer of metals or metal alloys is deposited on a superalloy substrate to seal the substrate against oxidation. A second layer of low density oxide is deposited on the surface of the primary layer. The primary layer has a rough surface so as to provide an adherent surface for the oxide layer.