The Preparation Of Titanium-based Diamond-like Carbon Gradient Film Materials And Their Biological Tribological Properties And Blood Compatibility

Diamond-like carbon gradient film on Ti6A14V alloy substrate have been prepared by means of plasma source ion implanted-ion beam enhanced deposition(PSII-IBED). For potential applications as artificial joint materials and artificial cardiac valve materials,its trobological performance and hemocompatibility has also been evaluated in the present Ph.D. thesis.The surface structure,morphology and internal thermal stress of DLC gradient film materials had been characterized or calculated. It was showed that the DLC gradient film has a smooth surface with noncrystal amorphous structure,its surface vicker's hardness was as about three times as that of Ti6A14V alloy substrate,and high adhension strength of no less than O.SGPa between DLC film and substrate was estimated by liquid quench method.The friction and wear behavior of DLC gradient film on TJ6A14V alloy substrate sliding against ultra-high molecular weight polyethylene was investigated by comparing with that of Ti6A14V alloy against the same counterpart under the same testing conditions. It has been found that the diamond-carbon-like gradient film has good friction-reduction and wear-resistant behavior in sliding against the polymer counterpart. The coefficients of friction reduced 24%,5.0%,10% than these of Ti6A14V under dry sliding and lubrication of Hank's solution and 0.9% NaCl solution respectively,and its wear rate were about half of that of T16A14V under the same condition. Especially,it also registered a lower wear rate of the polymer counterpart compared with Ti6A14V alloy. The worn surfaces of the tested samples were observed with a scanning electron microscope,as an effort to analyze the wear mechanisms. The wear of the diamond-carbon-like gradient film is characterized by slight abrasive wear which is able to be refrained by the polymer counterpart. Friction-reduction mechanism of DLC gradient film could be attributed to its smooth and hard amorphous structure.The hemocompatibility of DLC gradient film had been evaluated by investigating platelet consumption ratio,blood protein adsorption and plateletadhension and morphology on surface of materials. It showed that DLC gradient film had a better hemocompatibllity than T16A14V alloy since that DLC gradient film had lower adsorption ratio to blood protein and less effect on platelet adhension and morphology,though its platelet consumption ratio was almost as same as that of T16A14V alloy.The effect of friction and wear on hemocompatibility of materials was also investigated,since the hemocompatibility of bio-medical material is closely related to its surface structure and roughness. For comparison,that of the Ti6Al4V alloy sliding against UHMWPE was also evaluated. It was showed that DLC gradient film material had a good stability of hemocompatibility,for its surface almost had no changes. In comparison,the hemocompatibility of T16A14V became worse since its surface had been heavily scratched and dense oxide films on its surface had been destroyed.Fratal theory and image processing method had been applied to calculate the fratal dimension of tribological surfaces furthermore to elavuate the surface morphology and roughness. Evaluation on hemocompatibility of bio-materials had also been improved by image processing and analysis method,the relationship between mathematical morphological parameters of platelets adhered to bio-material surface and hemocompatibility of bio-materials had been established.