Synthesis of simple and platinum-modified aluminide coatings on cobalt (Co)-base superalloys via a vapor phase aluminizing process

An investigation was conducted to synthesize simple beta-CoAl or beta-(Co,Ni)Al coatings and platinum (Pt)-modified aluminide coatings on cobalt-base superalloys via an industrial vapor phase aluminizing process. Surface morphology and cross-section microstructure of the developed coatings were studied and compared by using optical microscope, scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). Experimental results showed that Al increase in Al-Cr nuggets increases the coating thickness; substrate elements influence the formation of coatings; the increase of the electrodeposited Pt thickness increases the amount of xi PtAl(2) phase after aluminizing process; and the transformation of xi PtAl(2) phase into beta-(Co,Ni,Pt)Al phase can be obtained via a heat treatment process. (C) 2008 Elsevier B.V. All rights reserved.