Characterization and tribological application of diamond-like carbon (DLC) films prepared by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) technique

Diamond-like carbon (DLC) films were successfully prepared on glass substrates and surfaces of selenium drums via radio frequency plasma enhanced chemical vapor deposition method. The microstructure, surface morphology, hardness, film adhesion, and tribological properties of the films were characterized and evaluated by X-ray photoelectron spectroscopy, atomic force microscopy, and micro-sclerometer and friction-wear spectrometer. The results showed that DLC films have smooth surfaces, homogeneous particle sizes, and excellent tribological properties, which can be used to improve the surface quality of the selenium drums and prolong their service life.     

超高分子量聚乙烯表面金属化及类金刚石薄膜沉积复合处理研究

采用超高分子量聚乙烯(UHMWPE)表面金属化及类金刚石薄膜沉积复合处理工艺,提高超高分子量聚乙烯的耐磨性.首先采用磁过滤阴极真空弧源沉积技术(FCVA)在UHMWPE表面制备约30nm钛金属层,使UHMWPE表面金属化,然后再沉积DLC薄膜,研究结果表明,UHMWPE表面金属化后,DLC薄膜沉积过程中,电荷累积效应消...     

Metal-doped (Ti, WC) diamond-like-carbon coatings: Reactions with extreme-pressure oil additives under tribological and static conditions

In contrast to non-doped diamond-like-carbon (DLC) coatings, reliable chemical evidence of the reactions between metal-doped DLC coatings and oil additives under tribological conditions using state-of-the-art surface-sensitive chemical analyses is still scarce. In this study we have investigated the reactivity of metal-doped (Ti, WC) DLC coatings with the extreme-pressure (EP) dialkyl dithiophosphate additive — without the presence of a steel counter body in the contact that befogs the actual coating reactions. Static “reactivity” experiments without any tribological or mechanical effects were also performed to provide a further insight into the lubrication mechanisms. The results confirmed the chemical reactions between the EP additive and all the DLC coatings, as well as their oxidation during the tribological contacts. We measured an about 10-times higher chemical activity (a 25-fold P/S ratio increase) for the Ti-doped DLC compared to the WC-doped or non-doped DLC, which also agrees with it having the lowest amount of wear in this study. We suggest that the Ti-DLC boundary lubrication is achieved via binding sites at the O vacancies present in the Ti-doped DLC coating. The data also clearly show, in contrast to most of literature reports, that even though small, some direct chemical activity between the W-DLC and the dialkyl dithiophosphate EP additive is also possible without any iron catalytic effect. However, the chemical changes were significantly smaller, also allowing coating graphitization, which might be one of the reasons for the 50% higher wear of the WC-doped compared to the Ti-doped DLC.