Corrosion resistance of CrALVN coatings deposited on PcrNi3Mo steel surfaces with reactive magnetron sputtering

Abstract

CrAlN and CrAlVN coatings were deposited on the surfaces of PCrNi3Mo steel substrates using reactive magnetron sputtering. The surface and cross-sectional morphology, hardness and elastic modulus, and crystalline-phase structure of the coatings were characterized with scanning electron microscopy, nano-indentation and X-ray diffraction, respectively. Electrochemical testing was employed for analyzing the corrosion resistance of the uncoated steel substrate and the substrates coated with the two protective materials. The results show that the average grain size of the CrAlVN coating is greater than that of the CrAlN coating, and the hardness and elastic modulus of the CrAlVN coating (24.98 GPa and 336.02 GPa, respectively) are significantly greater than those of the CrAlN coating (23.91 GPa and 316.2 GPa, respectively). The corrosion current densities of the CrAlN and CrAlVN coated substrates are greater than that of the uncoated PCrNi3Mo steel by factors of about 4 and 100, respectively. The electrochemical-reaction resistances of the CrAlN and CrAlVN coated substrates are greater than that of the uncoated steel by factors of about 13 and 25, respectively. While both coatings provided a substantially improved corrosion resistance, the CrAlVN coating performed better.