Corrosion behavior of novel Fe–Cr–B alloys containing high Cr content in molten aluminum

Abstract

Materials applied in the aluminum processing industry commonly suffer harsh corrosion on account of the high aggressivity of molten aluminum. Fe–Cr–B alloys have shown outstanding corrosion resistance to molten aluminum due to the presence of Cr‐rich borides displaying high stability. Accordingly, three Fe–Cr–B alloys with high Cr contents (20.6, 28.7, and 36.6 wt%) were fabricated in this study. As the Cr content increased from 20.6 to 36.6 wt%, the (Cr,Fe)2B borides ultimately transformed into Cr2B borides. A corrosion test was carried out in molten aluminum at three temperatures (700°C, 750°C, and 800°C) for 4 h and the volume losses of the studied alloys were measured to estimate their corrosion resistance. The Fe–Cr–B alloy with 28.73 wt% Cr exhibited the finest corrosion resistance among the three studied Fe–Cr–B alloys on account of enhancing the corrosion resistance of the Fe matrix by solution mechanism as well as maintaining the generation of periodical layered structures in its corrosion interface. In addition, as the test temperature expanded, the volume loss of Fe–Cr–B alloys stepped up slowly, whereas that of H13 tended to increase drastically.