The Platinum Development Initiative: Platinum-Based Alloys for High Temperature and Special Applications: Part IV

Abstract

Under the Platinum Development Initiative, platinum-based alloys were being developed for high-temperature and special applications for good corrosion and oxidation resistance. Parts I–III of the present series of papers dealt with the development of the ternary and quaternary Pt alloys (–). In this final paper (Part IV), the corrosion behaviour of selected Pt alloys treated with sodium sulfate salt was compared with that of coated and uncoated CMSX-4 ® nickel-based superalloy (NBSA). Scanning electron microscopy (SEM) results showed that protective alumina scales of different integrities formed on the Pt alloys, whereas the NBSAs failed rapidly even with an additional Ptaluminide protective coating. Although there were pits on the Pt alloys, they were minor and not visible to the unaided eye. The potential for application of these Pt alloys in the aerospace gas turbine industry was assessed based on their hot corrosion performance.