ABSTRACT

This chapter concerns the relatively thin protective coatings which today have an essential role in virtually all mechanical equipment that operates at high tempera­ tures. A great variety of methods are used to form such coatings in or on the surface region of the component to be protected and an even great variety of materials are employed as coatings. The prime function of a coating may be to act as a thermal barrier or to reduce friction, stiction, and wear, but the most widespread use to date is to protect from oxidation, corrosion, and erosion, this being particularly important in the hottest areas of gas turbines.