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BWD TURBINES LIMITED |
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ADVANCED TURBINE TECHNOLOGIES FOR THE INDUSTRY WORLDWIDE |
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Ceral10 is a silicon doped slurry diffusion aluminide coating specifically designed for use with superalloys. Ceral 10 provides excellent protection against high temperature oxidation as well as high temperature and low temperature hot corrosion. |
Ceral 10 |
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Compared with powder pack or CVD coatings Ceral10 has the following advantages:
- spray process simple as painting - simple diffusion process in furnace - spray process at room temperature - simultaneous diffusion of AI and Si - easy masking - easy repair of aluminide coatings - local coating possible - low cost of slurry - controlled coating thickness - no environmental problem with powder |
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Ceral10 is a silicon doped aluminide specifically designed for use with superalloys. Using Ceral10 coated alloy - heat treated - a uniform NiAI diffused aluminide coating is formed, with a silicon enriched layer on top. This layer is formed mainly by the possible silicides of the alloy: CrSi2 WSi2 TaSi2. Silicon enriched aluminides are known to provide for excellent protection against high temperature oxidation as well as high temperature and low temperature hot corrosion. This excellent performance is attributable to the low oxygen diffusion coefficients in Si02.
Ceral 10 is used in the form of a water-based slurry with aluminum and silicon. The slurry is sprayed onto a part cured at 200°C to form the ceramic binder which contains the aluminum and silicon. After this overlay coating has been built up, aluminum and silicon are diffused into the substrate by heating the part in a furnace to a temperature of between 870°C (with nickel base alloys) and 1090°C (with cobalt base alloys). The coating achieved shows very uniform thickness even on the edges of blades.
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A photomicrograph of the Ceral 10 Coating |