IMPROVEMENT OF HOT CORROSION RESISTANCE OF Ti3Al INTERMETALLIC COMPOUND BYIMPROVEMENT OF HOT CORROSION RESISTANCE OF Ti_3Al INTERMETALLIC COMPOUND BY SPUTTERED NiCrAlY COATING SPUTTERED NiC
(Corrosion Science Laboratory; Institute of Corrosion and Protection of Metals; Academia Sinica ; Shenyang 110015)
Abstract: The effects of sputtered NiCrAlY coating on hot corrosion resistance of Ti3Al intermetallics in the presence of(Na, K)2SO4 salts film at 950℃ in air were studied. It was shown that Ti3Al suffered from severe corrosion , forming a poor adhesive scale with an outer TiO2-enriched and inner Al2O3 enriched layer. The electrochemical mechanism was responsible for the corrosion process. The sputtered NiCrAlY coating can greatly improve corrosion resistance of Ti3Al by the the formation of a good adhesive Al2O3 enriched scale. But a-three-layer diffusion zone formed between coating and substrate alloy.
Key words: intermetallic compounds; Ti3Al NiCrAlY coating; hot corrosion