High-temperature erosion–oxidation of uncoated and FB-CVD aluminized and aluminized–siliconized 9Cr–1Mo steel under fluidized-bed conditions

Fluidized-bed combustion is one of the methods to generate energy in a clean and efficient way from a variety of fuels. However, conditions in fluidized-bed boilers: high temperature, oxidizing atmosphere and impacts by fluidized sand particles, can cause significant degradation of some boiler components, such as heat exchangers, by a combination of oxidation attack and erosion wear. Protective coatings, deposited mainly by thermal spraying and diffusion techniques, are considered a solution to extend the lifetime of such components. This paper allows evaluation whether diffusion coatings, applied using a fluidized-bed chemical vapour deposition (FB-CVD) technique, could be used to provide protection for 9Cr–1Mo steel against high-temperature erosion–oxidation.