Abstract: An improved aluminide coating especially for superalloy substrates. Slurry coating compositions of eutectic metal alloy powders and of non-eutectic metal powders, including an elemental powder of a silicide-former in a heat-curable liquid binder. A process for coating the substrates and the coated metal parts. The coatings have improved resistance to developing cracks and to hot corrosion and oxidation.

Abstract: An improved aluminide coating especially for heat resistant superalloy substrates. Slurry coating compositions of eutectic metal alloy powders and of non-eutectic metal powders. A process for coating the substrates and the coated metal parts. The coatings have improved resistance to developing cracks and to hot corrosion and oxidation.

Abstract: A silicon-enriched aluminide coating for a superalloy article has a composite microstructure including a plurality of bands of silicon rich phases (S.sub.1, S.sub.2, S.sub.3) and a plurality of bands of aluminum rich phases (A.sub.1, A.sub.2, A.sub.3), these bands being spaced apart through the thickness of the coating. The composite microstructure is created by depositing a slurry containing both silicon and aluminum in elemental or pre-alloyed form on the article and heating the coated article above the melting temperature of aluminum to cure the coating, the depositing and curing steps being repeated at least once before diffusion heat treating the resulting layers. Thereupon, all the above process steps are repeated at least once.

Abstract: A multiplex protective MCrAlY-based coating system for an M-based superalloy base material, where M is at least one of iron, cobalt and nickel, has a surface layer containing aluminides of platinum and the M constituent of the coating. There may be a single surface layer (FIG. 2) containing platinum modified aluminide, or alternatively a double surface layer (FIG. 3) in the form of a top layer containing platinum modified aluminide and a sub-surface layer containing aluminides substantially without platinum modification. The surface layer may also have extra chromium in solid solution in the M constituent of the coating, the chromium content in the surface layer of the coating being not more than about 40 wt. %, preferably 35 to 40 wt. %. The process for production of such a system involves deposition of an MCrAlY coating, optionally chrimizing it, and then aluminising and platinising it using appropriate amounts of platinum and appropriate heat treatments to obtain the desired variant of the coating system.