Reactive element modified chemical vapor deposition low activity platinum aluminide coatings

Abstract

Chemical vapor deposition (CVD) co-deposition of aluminum, hafnium, zirconium and silicon has been used to make reactive element modified low activity platinum aluminide coatings for gas turbine hardware. The controlled addition of reactive elements produces diffusion coatings with more than four times greater cyclic oxidation resistance than traditional two-phase type platinum aluminide coatings. In addition, the CVD co-deposition process removes harmful substrate impurities during aluminizing. The co-deposition process is outlined, the optimum coating structure and composition are discussed, bulk chemical analysis results from coated super alloy foils are summarized and the cyclic oxidation test data are presented.