Effect of microstructure optimization: Analysis of corrosion behavior of (ZrNbCrAlFe)1-xLax coating in high-pressure lithium borate solution

Considering the application environment of zirconium alloy , the (ZrNbCrAlFe) 1-x La x HEA coating was prepared on the surface of zirconium alloy by laser cladding . The Laves phase of the coating contains a large number of high angle grain boundaries . The addition of La 2 O 3 results in microstructure homogenization and grain refinement. It was found in electrochemical tests and high pressure corrosion of lithium borate solution at 360℃ that the refinement of grains promoted the formation of oxide film , and ZrO 2 and (Fe,Cr) 2 O 3 were preferantly formed on the coating. In addition, the Laves phase is the diffusion pathway for microcracks and elements during corrosion. • The distribution of high-angle grain boundaries was enhanced by the grain refinement attributable to La 2 O 3 . • The corrosion behavior of the (ZrNbCrAlFe) 1-x La x coating immersed in lithium borate solution for seven days was analyzed. • The oxidation of the (ZrNbCrAlFe) 1-x La x coating in high-pressure lithium borate solution at 360℃ were thoroughly analyzed. • The role of (Fe,Cr) 2 Zr as a diffusion channel and a microcrack propagation pathway in corrosion processes is discussed.