The sealing effect of Electrochemical Polarization and its influence on the Tribological Properties of CrN Coatings

The effects of scanning rate on the microstructure, mechanical and tribological properties of the CrN coatings were investigated. The results showed that the CrN coatings still presented a stable crystal structure comprising of CrN(111) after EP treatment. No diffraction peaks of chromium oxide were found in the X-ray diffractograms patterns (XRD).

However, the oxygen content of CrN coatings increased from 6.32 at% to 11.64 at%, and decreased gradually to 8.24 at% with the increasing of the scanning rate. It proved that only a small amount of amorphous chromium oxides was generated. These chromium oxides sealed the coating pores and decreased the porosity of the coating from 16.79 % to 10.83 % as a result, which increased the hardness by the degree of 21.2 %.