PROTECTIVE COATINGS IN THE GAS-TURBINE ENGINE

The gas turbine engine provides one of the harshest environments challenging material systems today. Engine components are subject to rigorous mechanical loading conditions, high temperatures, and corrosive or erosive media. Historically, engine manufacturers have applied protective coatings to increase the durability and field performance of alloys or composites. Field experience as well as the development of processing technologies has led to the evolution of many new and improved coating systems for a variety of engine component applications. In the fan and compressor areas, erosion-resistant coatings are used to minimize blade wear, antigallant coatings are used for fretting wear of blade root attachments and corrosion-resistant coatings are used for blade and disk materials. In the case of the combustor and turbine areas, diffusion and overlay coatings have been developed for oxidation and/or corrosion resistance and ceramic coatings are used widely as thermal barriers. In this paper, we shah review the current state of the art for coating technology in gas turbine engine applications with a look towards future needs and directions.