EFFECT OF HOT CORROSION AND OXIDATION ON COBALT - BASE SUPERALLOYS COATED BY ALUMINUM WITH PRESENCE OF THERMAL BARRIER ZRO2 AND MIXTURE OF (NACL) AND (NA2SO4) STEAMSALTSAT HIGH TEMPERATURES

The aim of the study was to investigate Mechanisms properties thermal barrier coatings (TBCs) enhance performance evaluation characteristics and develop TBCs.Cobalt –base superalloy has been used as a substrate zirconium stabilized Aluminum ceramic topcoat , in addition include degradation behavior system during cycling (3hr per cycle furnace) failure aluminized due thermally grown oxide (TGO) interface. fractures propagatethrough interface produce deformation bond coating . effect will result spallation TBCsand this is also corresponding slightdegradation .The steam salt (Nacl)and(Na2So4) mixture affecton lifetimes high temperature have strong which consistent with first order growth scale failer variation.