Analysis on behaviors of contact reaction between quenched Al-Cr foils and stainless steel

The Al-Cr alloy coating on 201 austenitic stainless steel surfaces was prepared by quenched Al-Cr foils. The interface microscopic analysis was carried out by OM, SEM and EDS. The structures and phase changes of quenched Al-Cr foils were analyzed by XRD and DTA. The results showed that the quenched Al-Cr alloy foils which were more than 8% of Cr contained precipitated phase Al₄₅Cr₇ at 720℃ that prevented the foils contact reaction with the stainless steel substrate. The foils which are less than 8% Cr could react with the substrate, and formed metallurgical bonding. The Al-Cr alloy coating was composed of Cr, Ni, Mn contained FeAl₃, Fe₂Al₅, FeAl and so on from outside to the inside. The reaction mechanism was also discussed.