Effect of diffusion on coating microstructure and oxidation resistance of aluminizing steel

À´Ô´ÆÚ¿¯£ºÖйúÓÐÉ«½ðÊôѧ±¨(Ó¢ÎÄ°æ)2001ÄêµÚ6ÆÚ

ÂÛÎÄ×÷ÕߣºÏÄÔ­ ÓÚÉýѧ Ҧö ÀîÌú·ª

ÎÄÕÂÒ³Â룺817 - 821

Key words£ºhot-dip aluminium; dip diffusion aluminum; oxidation resistance at highª²temperature; surface coating; microstructure

Abstract: 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¡æ, the coating consists of thick outer surface layer (Fe₂Al₅+FeAl₂), thin internal layer (FeAl+stripe FeAl₂), and its oxidation resistance is poor. After diffusion at 950¡æ, the outer surface layer is composed of single FeAl₂ 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¡æ, the outer surface layer becomes thinner and consists of FeAl₂+Fe₂Al₅ (small amount), the internal layer becomes thicker and consists of FeAl+spherical FeAl₂£¬and the spheroidized FeAl₂ phase in the internal layer and its existing in FeAl phase steadily improve the oxidation resistance of the coating.