Sulzer offers coatings and Stellite® hard-facing designed to reduce losses in efficiency and help maintain steam turbine performance.
- Air spray coatings such as A21 and A24 protect airfoils against corrosion and reduce fouling. These metallic-ceramic coatings improve and maintain surface finish.
- Each coating contains an aluminum-chromate-phosphate base coat to provide sacrificial cathodic protection from corrosion.
- The active coating layer acts as an anode to protect the less active base metal. An inorganic sealer improves surface finish and extends the life of the coating.
- A24 contains a third inorganic layer impregnated with Polytetrafluoroethylene (PTFE) to provide anti-fouling characteristics.
- Thermal spray coatings, such as High Velocity Oxygen Fuel (HVOF) chrome carbide, improve erosion protection.
- Chrome carbide coatings have a hardness level over 60 HRc.
- Stellite® and other hard facings can also be coated, welded, or brazed onto steam turbine blades in order to resist erosion.