Preparation and hot corrosion behaviour of Pt modified AlSiY coating on a Ni-based superalloy

A Pt modified AlSiY coating was prepared on a Ni-based superalloy DD5 by electroplating and arc ion plating (AIP). The outer layer of the coating was mainly composed of β-(Ni,Pt)Al with dispersed CoWSi. The hot corrosion behaviour of Pt modified AlSiY coating at 900 °C was investigated. Compared to AlSiY coating, the Pt modified AlSiY coating provided improved hot corrosion resistance. The addition of Pt in AlSiY coating accelerated the phase transformation from θ-Al2O3 to α-Al2O3 in the initial stage, improved the scale adhesion and effectively suppressed the formation of internal oxides and internal sulphides.