DLC膜厚度对镁基表面DLC/MAO复合膜层性能的影响

采用线性离子束沉积技术于AZ80镁合金微弧氧化(MAO)陶瓷层表面沉积不同厚度的类金刚石碳(DLC)膜,形成DLC/MAO复合膜层.对比研究4种膜基系统的表面结构特征、力学性能以及摩擦学性能差异.结果表明:随DLC膜厚度增加,复合膜层表面微孔数量减少,孔径减小,但凹凸不平趋势增加,且DLC膜表面颗粒特征更加明显,表现为DLC-80min/MAO/AZ80膜基系统具有最小的表面粗糙度,最大的硬度H、弹性模量E及H/E值;不同厚度DLC/MAO/AZ80膜基系统平均摩擦因数较MAO/AZ80显著降低;DLC膜厚度增加导致3种复合膜基系统的表面微观结构改变,使得摩擦因数与磨痕形貌存在差异;各膜基系统

Effect of DLC Film Thickness on Properties of DLC/MAO Composite Coating on Magnesium Alloy

Diamond-like carbon(DLC) films with different thickness were deposited using ion beam deposition technique on the coated AZ80 magnesium alloy pretreated by microarc oxidation(MAO),forming the DLC/MAO composite coating.The surface microstructure,mechanical and tribological properties of the four film-substrate systems were studied.The results show that,increasing the thickness of the DLC film,the numbers and aperture of the micropores on the composite coating surface decreased.However,the composite coating surface changed coarse and more grains distributed on the DLC film with the increasing of thickness.As a result,DLC-80min/MAO/AZ80 film-substrate system had the lowest Ra and the maximal H,E and H/E.Compared with the MAO coating,the average values of friction coefficient of the DLC/MAO composite coating decreased.The friction coefficient and wear morphologies of the film-substrate systems with different thickness of DLC film exhibited difference due to the change of surface characteristic.The Fe transfer layer were formed on the wear surface of all the film-substrate systems.The coated Mg alloy was effectively protected for the lubrication characteristic of the surface DLC film.