Effects of strain-induced melt activation treatment on the microstructure and properties of Zn sacrificial anodes

The microstructural properties and electrochemical performance of zinc (Zn) sacrificial anodes during strain-induced melt activation (SIMA) were investigated in this study. The samples were subjected to a compressive ratio of 20%–50% at various temperatures (425–435°C) and durations (5–30 min). Short-term electrochemical tests (anode tests) based on DNV-RP-B401 and potentiodynamic polarization tests were performed in 3.5wt% NaCl solution to evaluate the electrochemical efficiency and corrosion behavior of the samples, respectively. The electrochemical test results for the optimum sample confirmed that the corrosion current density declined by 90% and the anode efficiency slightly decreased relative to that of the raw sample. Energy-dispersive X-ray spectroscopy, scanning electron microscopy, metallographic images, and microhardness profiles showed the accumulation of alloying elements on the boundary and the conversion of uniform corrosion into localized corrosion, hence the decrease of the Zn sacrificial anode’s efficiency after the SIMA process.