Adhesion, microstrain, and corrosion behavior of ZrN-coated AZ91 alloy as a function of temperature

In this study, nanocrystalline ZrN films were successfully deposited onto AZ91 alloy using an ion beam sputtering method at substrate temperatures of 373–673 K. Strain and adhesion were calculated using the classic Williamson–Hall and indentation cracking methods, respectively. Microstructure and crystalline properties were evaluated using scanning electron microscopy and x-ray diffraction. XRD results showed that the crystallographic properties of the films were strongly dependent upon substrate temperature. An increase in temperature increased adhesion of the film to the AZ91 alloy and decreased film microstrain. The corrosion behavior of ZrN/AZ91 samples in Ringer’s solution was studied to evaluate corrosion potential and corrosion current density. Potentiodynamic corrosion tests showed that all ZrN-coated samples had a corrosion resistance superior to the blank substrate, mainly at 400 °C. A correlation was also established between vacancy defects in the film and corrosion behavior.