Abstract:

Investigation of distribution and existence mode of silicon in Al-Si coatings has been carried out. It reveals that a Si-rich barrier may be formed between the Si-containing aluminide coaling and substrate. The barrier impedes diffusion of Al and Si in the aluminide coating into the substrate, therefore the resistance of the coatings to oxidation at high temperature is improved. Pretreatment enables the Si-rich barrier to be preformed in the Al-Si coatings. Consequently the protective capability of the Al-Si coatings is enhanced.