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The effect of diffuse treatment on coating microstructure and oxidation resistance at high temperature of hot dip aluminum were studied by means of TEM, SEM and XRD. The results show that, the diffusion temperature has significant effect on structure of coatings and its oxidation resistance. After diffusion at 750?℃, the coating consists of thick outer surface layer (Fe 2Al 5+FeAl 2), thin internal layer (FeAl+stripe FeAl 2), and its oxidation resistance is poor. After diffusion at 950?℃, the outer surface layer is composed of single FeAl 2 phase, the internal layer is composed of FeAl phase, and its oxidation resistance declines due to the occurrence of early stage internal oxidation cracks in the coating. After diffusion at 850?℃, the outer surface layer becomes thinner and consists of FeAl 2+Fe 2Al 5 (small amount), the internal layer becomes thicker and consists of FeAl+spherical FeAl 2, and the spheroidized FeAl 2 phase in the internal layer and its existing in FeAl phase steadily improve the oxidation resistance of the coating.
The results of diffuse treatment on coating microstructure and oxidation resistance at high temperature of hot dip aluminum were studied by means of TEM, SEM and XRD. The results show that, the diffusion temperature has significant effect on structure of coatings and its oxidation resistance. After The coating consists of a thick outer layer (Fe2Al5 + FeAl2), a thin internal layer (FeAl + stripe FeAl2), and its oxidation resistance is poor. After diffusion at 950 ° C, the outer surface layer is composed of single FeAl 2 phase, the internal layer is composed of FeAl phase, and its oxidation resistance declines due to the occurrence of early occurrence of internal oxidation cracks in the coating. After diffusion at 850 ° C., the outer surface layer becomes thinner and consists of FeAl 2 + Fe 2Al 5 (small amount), the internal layer becomes thicker and consists of FeAl + spherical FeAl 2, and the spheroidized FeAl 2 phase in the internal layer and its existing in FeAl phase steadily improve the oxidation resistance of the coating.