Abstract: A method for improving the corrosion and fatigue crack resistance of an article that has a surface. The method involves: providing a dry powder having one or more anti-corrosion materials; pressurising the dry powder to 1 to 5 MPa in an inert gas; pre-heating the surface of the article to a temperature of 50 to 900° C. and cold-spraying the surface of the article with the dry powder at a particle velocity of 300 to 1200 m/s so that a corrosion and crack-resistant coating is formed on the surface of the article and the surface is modified to an average depth of 10 to 100 ?m.

Abstract: The present disclosure relates to a thermal barrier coating for coating a substrate. The thermal barrier coating may comprise an inner ceramic layer (e.g. 7YSZ) having a columnar grain structure and a first outer ceramic layer (e.g. 7YSZ) having a branched grain structure. The thermal barrier coating further comprises a nucleation layer (which may comprise alumina or tantala), interposed between the inner ceramic layer and the first outer layer. The layers can be deposited by PVD using substantially contact deposition parameters because the nucleation layer induces branching in the first outer ceramic layer.