protective coating to metal
Patent No. U.S. 6,565,931 B1
Rolls-Royce plc, has patented a method of applying a corrosion protective coating to a region of metallic article. It is comprised of applying a layer of platinum-group metal to the region of the metallic article, the region of the metallic article comprising a gamma phase and a gamma prime phase, heat treating the metallic article to diffuse the platinum-group metal into the metallic article and create a platinum-group metal enriched outer layer on the metallic article, the heat treatment carried out at a temperature and for a time sufficient that the platinum-group metal enriched outer layer of the metallic article predominantly comprises a platinum-group metal enriched gamma phase and platinum-group metal enriched gamma prime phase, wherein the metallic article is a turbine blade and the turbine blade comprises an aerofoil, a platform, a shank and a root, and the coating is applied to the root and/or shank of the turbine blade and the coating on the root and/or shank consists essentially of the platinum-group metal enriched outer layer.