Insight into the pitting corrosion behavior of laser‐welded R60702 zirconium alloy in chloride electrolyte

Abstract

AbstractThis work aims to analyze the passivation and pitting corrosion behaviors of laser beam welded R60702 zirconium alloy in neutral and acidic chloride‐containing electrolytes. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements are carried out to investigate the electrochemical performance of the welding joint. Scanning electron microscope, X‐ray diffraction, and three‐dimensional profile digital microscope are utilized to reveal the microstructures and corrosion morphologies. The electrochemical results show that the heat‐affected zone (HAZ) and weld zone have nearly equal corrosion performance, and both of them are more corrosion‐resistant than the base metal. The corrosion morphologies suggest that the HAZ has the lowest sensitivity to pitting corrosion. Moreover, it is unraveled that, in chloride‐containing electrolytes, the quantity and distribution of Zr(Fe,Cr)2 particle phases are the main factors that determine the different corrosion performances of the welding joint.