Probing the friction and wear behaviors of diamond-like carbon film in HCl and H2SO4 media

Abstract

Diamond-like carbon (DLC) films combine excellent chemical inertness and wear resistance, opening the feasibility for its application in harsh acidic environments. In this work, DLC film was deposited on 304 stainless steel (304 SS) by unbalanced magnetron sputtering technology, and the tribological behaviors and corrosion resistance (excepting deionized water) of deposited DLC film in deionized water, 1 M NaCl, 1 M HCl and 0.5 M H2SO4 were comparatively probed. Results indicated that the deposited DLC film presented the lowest friction coefficient and wear rate in 1 M HCl solution, which might be attributed to the boundary lubrication of HCl and tribochemical products, as well as lubrication of graphitization. The relatively high friction coefficient and wear rate of deposited DLC film in 0.5 M H2SO4 solution were mainly related to the smallest graphitization, higher viscosity and adhesive wear of debris cluster. By contrast, the pitting effect of Cl− for deposited DLC film was boosted in 1 M HCl solution due to the enlarged hole of H+, resulting in the corrosion resistance of deposited DLC film in 1 M HCl solution become worse than that in 0.5 M H2SO4 solution. Meanwhile, these two acidic media alleviated the wear during sliding combined with deionized water. In the four test environments, the optimization effect of deposited DLC film for 304 SS substrate was most obvious in 0.5 M H2SO4 solution and 1 M HCl solution. It can be concluded that the deposited DLC film can provide an exceptional protectiveness for 304 SS substrate in 0.5 M H2SO4 solution and 1 M HCl solution.