The mechanical and tribological properties of CrBN-Ni-Cu-O coatings with different Ni and Cu contents

Based on the advantages of Ni or Cu incorporation to the mechanical and tribological properties of nitride coatings, the co-incorporation of Ni and Cu at different ratios was employed on CrBN coatings. Results showed that Ni (11.01 at%) and Cu (3.41 at%) co-incorporation increased hardness from 24.4 GPa to 26.4 GPa. As a consequence, coatings wear rate decreased from 6.4 × 10⁻⁷ mm³/Nm to 5.4 × 10⁻⁷ mm³/Nm. At the meantime, friction coefficient declined from 0.30 to 0.28 due to CuO lubricating layer. However, when Cu content was high (10.68 or 15.05 at.%), the hardness of Ni-Cu-CrBN coatings sharply declined, which weakened wear resistance and increased friction coefficient. It indicated that Ni (11.01 at%) and Cu (3.41 at%) was the proper co-incorporation combination.