Abstract:A nitride layer was first formed on Cr12MoV steel samples by plasma nitriding and then a CrNiTiN coating was prepared on the surface of nitrided and non-nitrided Cr12MoV steels using closed field unbalanced magnetron sputter ion plating. The coatings were characterized in terms of their structure , adhesion strength and abrasion resistance were compared between nitrided and non-nitrided Cr12MoV.The surface free energy of the coatings was calculated using the Qwens-Wendt geometric mean approach. The experimental results indicated that both low total surface energy (11.22mN/m) and poor adhesion strength (43N) could be obtained in the CrNiTiN coating. The high adhesive strength was achieved when Cr12MoV steel was treated with plasma nitriding , leading to the enhanced load strength between CrNiTiN films and substrate. The friction coefficient and wear rate of CrNiTiN coatings on plasma nitriding treated Cr12MoV steel substrate is far less than that of untreated one .The duplex treatment of plasma nitridation and CrNiTiN coatings could increase the total surface energy.