Corrosion behavior of a Co-Cr-Mo-Si alloy in pure Al and Al-Si melt

Abstract

Metallic phase change materials (MPCMs) are attracting considerable attention for their application in thermal energy storage. Al-Si alloys are considered potential MPCMs; however, to develop storage systems/modules, it is crucial to fabricate corrosion-resistant materials for MPCMs. In this study, the corrosion behavior of Co-28Cr-6Mo-1.5Si (wt%) alloy was examined via immersion tests in commercial Al-Si alloy (ADC12) melt at 700°C for 10 h. The results were compared to those obtained for pure Al. Substrate thickness loss measurements revealed that the liquid metal corrosion was more severe in the Al-Si melt than that in pure Al, suggesting an increased reactivity due to Si addition. Interfacial analysis elucidated a direct reaction between the alloy substrate and molten Al in both cases. Furthermore, the formation of oxides such as Al2O3 and SiO2 did not contribute to corrosion resistance.