Effect of ultrasound assistance on the mechanical performance and corrosion resistance of Zn-Ni coatings produced by cathode plasma electrolysis deposition

Abstract

Zn-Ni coatings were fabricated via ultrasonic-assisted cathodic plasma electrolysis deposition (US-CPED) technology. The results demonstrate that ultrasonic assistance can significantly affect the deposition and growth process of Zn-Ni coatings, which is attributed to ultrasonic vibration reducing the diameter of bubbles and inducing a more uniform distribution of the vapor gaseous envelope (VGE) on the surface of the substrate. The Zn-Ni coatings with more homogeneous microstructure were formed due to the more uniform plasma discharge process on the surface of the substrate based on the VGE uniform distribution. Compared to the Zn-Ni coatings without ultrasonic assistance, the thickness and roughness of Zn-Ni coatings with ultrasonic assistance increased by >80 % and decreased by over 40 %, respectively. Better Zn-Ni coating quality brings higher corrosion resistance. In addition, ultrasound can accelerate the iteration of bubbles in VGE to enhance the work-hardening effect, improving the mechanical properties of the Zn-Ni coatings. This work introduces a novel insight into the controllability of the CPED process and paves the way for exploring other methods to stabilize the CPED process.