Plasma Spray Coatings for Superalloys

Superalloys are well known materials for§high temperature applications. Although the§superalloys have adequate mechanical strength at§elevated temperatures, yet they often lack resistance§to oxidizing/corroding environments during long time§exposures. One possible way to combat the problem§constitutes the use of protective coatings on the§superalloys. Among the various techniques used for§deposition of coatings, plasma spraying is a§versatile technology that has been successful as a§reliable cost-effective solution for many industrial§problems.In the present book, high temperature§oxidation behavior of some Ni- and Fe- based§superalloys has been explained with and without the§application of plasma sprayed coatings in air, as§well as, in a simulated boiler (Na2SO4-60%V2O5)§environment.Characterization and high temperature§oxidation behavior of four coatings; Ni-22Cr-10Al-1Y§(NiCrAlY), Ni-20Cr, Ni3Al and Stellite-6 has been§elaborated with the help of Optical microscopy,§Scanning Electron Microscopy/Energy Dispersive§Spectroscopy and Electron Probe Micro Analysis.The§effectiveness of the coatings has been discussed on§the basis of weight change data.