Enhancing corrosion behavior of CrN coating through oxygen incorporation: Experimental and theoretical analyses

This study examines the corrosion behavior of Cr-O-N coatings under different corrosive conditions, placing particular emphasis on how oxygen content affects their behavior. The combined experimental and theoretical findings underscore the superior attributes of coatings that contain oxygen. Incorporation of oxygen atoms serves to refine the grain size, thereby increasing the number of grain boundaries. This refinement effectively impedes the penetration speed of erosive ions, resulting in improved corrosion resistance. Of significant interest is the activity of the electrochemical reaction, which can be observed to decrease systematically from CrN to Cr-O-N coatings as the oxygen content increases. Both of these factors synergistically contribute to enhance the corrosion resistance of the Cr-O-N coatings. Furthermore, the samples exposed to NaCl solution exhibit better corrosion properties than those in H2SO4 solution.