Preparation and oxidation performance of a low-diffusion (Ni,Pt)Al coating with an in-situ formed α-W based diffusion barrier

A quasi-continuous α-W-based diffusion barrier (DB) forms in-situ between the (Ni,Pt)Al and the inter-diffusion zone by adding a Ni-W plating layer before the coating preparation. The oxidation behavior of the DB-contained coatings is compared with the normal (Ni,Pt)Al coating at 1100 ℃. The results indicate that the (Ni,Pt)Al with DB exhibits lower oxidation rate, slighter inter-diffusion and flatter surface. Additionally, martensite was observed in (Ni,Pt)Al-DB coatings, which contributed to lower surface rumpling for its higher stiffness and better resistance to creep. The mechanism of the DB and its effects on the oxidation performance of the (Ni,Pt)Al coating were discussed.