Thermal spray technology is already well established in the power generation industry, specifically in land based gas turbine manufacturing, where plasma sprayed thermal barrier coatings (TBC’S) are commonly applied. TBCs fulfill the functions of thermal insulation by lowering the temperature of hot gas washed surfaces. The temperature in the combustion chamber exceeds 1300°C, therefore TBCs are used to limit the overheating of blades, vanes and combustion chambers above approx. 950°C, a long term operation temperature limit for super-alloys. Typical thermal barrier coatings are multi-layer systems based on a duplex structure, a dense metallic bond coat layer (typically MCrAlY) providing corrosion/oxidation resistance and strong adhesion for top thermally insulating ceramic layer (typically Yttria Stabilised Zirconia – YSZ).
Thermal spray coatings applications in Power Generation industry include:
- Combustor cans
- Transition ducts
- Abradable seals