Investigation About Wear Resistance Of DLC Films Deposited On The Surface Of Uhmwpe

The ultra-high-molecular-weight polyethylene (UHMWPE) has been widely used as orthopedic joint materials. However, over long periods of time, wear debris of UHMWPE will cause deleterious biological reactions which is believed to be the main cause of later osteolysis and aseptic loosening. Therefore, improving the wear resistance of UHMWPE to resolve this problem is really necessary. Because Diamond-like Carbon(DLC) film which has low friction efficient is an excellent surface antiwear and modified film, DLC film had been deposited on the surface of UHMWPE to improve its wear resistace in our laboratory, but it was found that there were severe bad charge accumulating and combination between film and UHMWPE. In order to resolve these problems, two experimetal approaches were proposed in the paper, one is Ti metallization on the surface of UHMWPE and deposition of DLC film, the other is pretreatment of oxgen plasma conducted by metal screen grid and deposition of DLC film.During the experiment that Ti metallization on the surface of UHMWPE and deposition of DLC film, Ti transition layer adherence prepared by FCVA and UBMS techniques had been evaluated, and effects of Ti transition layer on the structure, hardness and wear resistance of DLC film also had been investigated. The results showed that better Ti transition layer could be prepared by FCVA technique, and this Ti transition layer also could improve electrical conductivity of UHMWPE and decrease charge accumulating. Therefore, DLC film deposited on this Ti transition layer had more sp3bonds and less hydrogen, and its depositon rate, hardness, film-substrate adhesion and wear resistance had been improved.During the experiment that UHMWPE was prtreated by oxygen plasma conducted by metal screen grid, effects of bias voltage and diastance between sample and metal grid on the surface structure, surface topography, hydrophilicity, mechanical property and wear resistance of UHMWPE had been investigated. It was found that the degree of crosslinking, oxidation, wettability and surface roughness of UHMWPE had been increased with the increasing of the screen-grid voltage, and the wear performance could be improved for UHMWPE treated at-100V bias voltage. Additionally, when the distance between sample and metal grid was30mm, low degree of crosslinking, oxidation, wettability and surface roughness were obtained on the surface of UHMWPE, and this caused hardening with toughness maintained on the surface of UHMWPE, so maybe a appropriate proportion was achieved between brittleness and toughness, a pefect wear performance was obtained at30mm.During the experiment that pretreatment of oxgen plasma conducted by metal screen grid and deposition of DLC film, effects of the pretreatment process of oxygen plasma on hardness, film-substrate adhesion and wear resistance had been studied. It was found that the pretreatment process of oxygen plasma could improve hardness, croop property and film-substrate adhesion of DLC film and extend the bearing time of DLC film in the wear test.Comparing effects of Ti metallization on the surface of UHMWPE and the pretreatment of oxgen plasma conducted by metal screen grid on the film-substrate adhesion and wear resistance of DLC film, it was found that’Ti metallization on the surface of UHMWPE and deposition of DLC film’could resolve bad charge accumulating and combination between film and UHMWPE effectively, and extend the bearing time of DLC film in the wear test.