Effect of metal vapor vacuum arc-implanted Cr on the electrochemical behavior of CrN-coated steels

Abstract

Using cathodic arc plasma to deposit CrN on the steel has been explored and extensively studied to improve the wear and corrosion resistance of the steel structures. Metal vapor vacuum arc (MEVVA) source implantation is a novel and profitable surface-modification process coupled with the cathodic arc plasma. The effect of the MEVVA-implanted chromium on the corrosion behavior in form of Cr/steel, CrN/steel, and CrN/Cr/steel was evaluated in an aerated 0.1N HCl solution. The composition and structure of the MEVVA-implanted chromium and the cathodic arc plasma deposited CrN on steel were both examined by x-ray diffraction and transmission electron microscopy. The polarization resistance (Rp) of all samples was measured and compared with the results obtained from electrochemical impedance spectroscopy simulated by the equivalent circuit, to interpret the effect of MEVVA-implanted chromium on the corrosion mechanism of the CrN/Cr/steel. The corrosion products associated with the microstructures were analyzed by electron probe x-ray microanalyzer. The results indicated that the corrosion resistance of the CrN-coated steel was significantly enhanced by the MEVVA-implanted chromium in the CrN/Cr/steel assembly.