Oxidation behaviour of (Ni,Pt)Al coating with an in-situ formed α-W diffusion barrier: The effect of the diffusion barrier thickness

(Ni,Pt)Al coating with varying thicknesses of α-W-based diffusion barrier (DB) were prepared by adding various thicknesses of NiW plating layer. The oxidation performance of the DB-contained coatings was compared to that of the normal (Ni,Pt)Al coating at 1100 °C. With the thicker of DB, the inter-diffusion of Ni, Al as well as the refractory elements was more effectively inhibited. Moreover, better oxidation resistance was observed on (Ni,Pt)Al coating with a thicker DB, exhibiting a lower oxidation rate, flatter surface rumpling extent and slower phase degradation rate. The effects of DB on the inter-diffusion behaviour and oxidation performance of the (Ni,Pt)Al coating are discussed, and the degradation mechanism of the DB is proposed.