Industries / Power generation
Power generation
Reliability and efficiency for power equipment.
Protection of critical components against high temperatures, corrosion, oxidation and erosion. Applications include turbines, boilers, pumps, valves and hot-gas paths.
Components and protection zones
Boiler tubes
Protection against high-temperature oxidation and corrosion.
- Zones:
- External waterwall and superheater surfaces; internal corrosion zones.
- Coatings / bond coat:
- Diffusion aluminides (NiAl); MCrAlY; Sealing systems
- Substrate:
- Carbon and chromium-molybdenum steels.
Burner nozzles
Protection against hot corrosion, oxidation and erosion.
- Zones:
- Flame impingement areas and hot-gas flow surfaces.
- Coatings / bond coat:
- NiCrAlY; YSZ
- Substrate:
- Heat-resistant steels and nickel alloys.
Steam and gas turbine blades
Reduced heat exposure and protection against hot-gas corrosion.
- Zones:
- Airfoils, leading edges, tips and platforms.
- Coatings / bond coat:
- YSZ; MCrAlY (bond coat, if required)
- Substrate:
- Nickel-based superalloys.
Fan and blower impellers
Protection against erosion by particle-laden gas streams.
- Zones:
- Blade leading edges and pressure-side surfaces.
- Coatings / bond coat:
- WC-CoCr or Ceramic systems
- Substrate:
- Carbon and stainless steels.
Ash-handling ducts and elbows
Erosion and wear protection during ash transport.
- Zones:
- Ash impact areas, bends and transitions.
- Coatings / bond coat:
- Cr3C2-NiCr or Ceramic systems
- Substrate:
- Carbon and stainless steels.
Turbine seals and valve seats
Maintaining operating clearances and sealing integrity.
- Zones:
- Shrouds, seal rings, seats and plug surfaces.
- Coatings / bond coat:
- Engineered system selected for the service environment
- Substrate:
- Heat-resistant and structural alloys.
Economisers and air-preheater fins
Corrosion protection while maintaining heat transfer.
- Zones:
- Heat-transfer and fin surfaces.
- Coatings / bond coat:
- Engineered system selected for the service environment
- Substrate:
- Boiler steels and alloys.
Materials and applications
| System | Materials | Application |
|---|---|---|
| Thermal barrier ceramic | YSZ (ZrO2 / Y2O3) | Turbine blades, vanes and combustor liners. |
| Oxidation and hot-corrosion resistant metallic | MCrAlY, NiAl, FeCrAl | Boiler tubes, burner nozzles and hot-gas paths. |
| Wear-resistant carbide | WC-CoCr, Cr3C2-NiCr | Ash handling, fans, impellers and valves. |
| Wear-resistant ceramic | Cr2O3-TiO2, SiC | Erosion-prone ducts, elbows and cyclones. |
| Sealing layers | Al2O3, MCrAlY, SiO2 | Sealing, diffusion control and protection of thermal barrier systems. |
Coating structure
- Functional layer
- Bond coat, if required
- Component material
Schematic, not to scale. Layer count and bonding mechanism depend on the selected material and process.
Coating processes
- HVOF
- APS
- VPS
- Cold spray (CS)
- HVAF
Typical applications, not a component specification. Composition, thickness, surface preparation and acceptance criteria must be selected for the operating conditions and validated by testing.