Corrosion of Copper in a Concentrated LiNO₃ Solution at a High Temperature

摘要

This paper presents the effects of the concentration, temperature, pH and Li2CrO4 on copper corrosion in a concentrated LiNO3 solution. The LiNO3 concentration had opposite effects on the copper corrosion. The corrosion rate increased with increasing temperatures, but decreased with increasing pH levels. Below 220 °C, Li2CrO4 promoted the formation of a thin and compact passive film comprising CuO, Cu2O and Cr2O3, which effectively inhibited the copper corrosion. Regarding corrosivity, the maximum applicable temperature for an absorption heat pump was extended from 165 °C to 220 °C using a LiNO3 solution instead of a LiBr solution as the working fluid.