Deposition, microstructure, performance of diamond-like carbon film with Ni/Cu interlayer

Diamond-like carbon (DLC) films containing single copper (Cu), single nickel (Ni) and double nickel/copper interlayers were fabricated on LY-12 aluminum (Al) alloy by electrodeposition. The influence of different interlayers on the microstructure, microhardness, friction and wear properties and electrochemical behavior of the films was investigated. The morphological results show that the porosity of DLC films was reduced and the particles were refined after the introduction of a double interlayer. Raman and X-ray photoelectron spectroscopy results confirm that the amorphous characteristics of DLC films containing nickel and copper interlayers were enhanced, and the content of sp³ carbon in the films was increased. Besides, an optimal microhardness of 210.67 HV was achieved due to the high sp³ carbon content of the double nickel/copper–DLC film. Meanwhile, the nickel/copper–DLC film possessed excellent wear resistance, which benefits from the synergistic effect of the copper and nickel interlayer. Nickel as the supporting layer and copper as the lubricating layer alleviated the wear and friction of the film. Simultaneously, the deposition of a double interlayer increased the density of the film, which further prevented the invasion of corrosion ions, so the film had superior electrochemical properties.