The improved mechanical and tribological properties of CrN coatings sealed via electrochemical polarization treatment

In order to seal the void defects in CrN coatings so as to enhance its mechanical and tribological properties, the electrochemical polarization treatment at different over-potentials was employed. The results showed that the maximum content of oxygen was increased by 1.22 at% after electrochemical polarization treatment, but the crystal structure of CrN(111) and Cr₂N(002) for CrN coatings remained stable. The formation of a little chromium oxides as expected sealed the CrN coatings pores, and therefore lowered its porosity from 16.79 % to 12.28 %. As a result, the maximum hardness was increased by 20.3 %. Moreover, the wear resistance of CrN coatings was enhanced by 29.9 % whilst the friction coefficient was reduced by 25.2 % at the over-potential of 70 mV. © 2024 Elsevier Ltd.