Comparison of mechanical and tribological properties of CrBN coatings modified by Ni or Cu incorporation

To compare the merits of Ni and Cu,the mechanical and tribological properties of CrBN coatings modified by Ni or Cu incorporation were studied.The results demonstrated that the CrBN–Cu coatings presented a lower friction coefficient than CrBN and CrBN–Ni coatings owing to the improved lubrication effect of the CuO layer originating from the tribochemical reaction.However,the hardness decline due to Cu incorporation was much greater than that of Ni incorporation.Thus,the CrBN–Cu coatings exhibited a higher wear rate than the CrBN coating.In contrast,the plastic deformation enhancement induced by Ni incorporation exceeded the hardness decline.Therefore,the wear of CrBN–Ni coatings partially turned to plastic deformation to present a lower wear rate than that of the CrBN coating.