| Diamond-like carbon (DLC) films have been used widely as biomaterials because of their good biocompatibility and blood-compatibility. DLC films can be deposited by chemical vapor deposition and physical vapor deposition. Temperature of deposition is high, so high thermal stress always exists in interface of film and substrate and results in bad adherence of the films to substrates. Liquid-deposition is a new method of depositing DLC film. It proceeds under room temperature and normal press by electrolysis of organic liquid and it solves the problem of high thermal stress in interface. DLC films are Diamond-like carbon (DLC) film is amorphous carbon film. DLC film is widely used as biomaterials because of its good chemical stability, bio-compatibility, hardness, high antifriction, high resistance and good IR transmission.DLC films can be prepared by chemical vapor deposition(CVD) and physical vapor deposition(PVD). DLC films deposited by CVD and PVD have some disadvantages as follows: (1) Because temperature of deposition is very high, thermal stress in the interface forms after deposition and may result in bad adhesion of the coating to substrate. (2) Technology of deposition is strictly and equipment is costly.Liquid-deposition is a new method of depositing DLC film. It proceeds under room temperature and normal press by electrolysis of organic liquid and it solve the problem of high thermal stress in interface. Now DLC films can be deposited on surface of Si, conductive glass and Al by liquid-deposition, but it has not been reported that DLC film can be deposited on surface of Ti alloy by this way. Application of DLC films deposited by liquid-deposition is now limited to electronics and has not begun as biomaterial.Liquid-deposition has many advantages. (1) Because reaction proceeds in liquid phase, it is easier to control condition of reaction and to acquire regular coatings than in gas phase. (2) There is no remarkable change of temperature before and after deposition, so thermal stress does not exit in interface and adherence between DLC and substrate is strong. (3) Equipment of deposition is cheaper. Energy and material will be saved by thisway. It is easier to deposit DLC films massively by liquid-deposition. Therefore, study on preparation of DLC films by liquid-deposition and application as biomaterials is important.This work is supported by Nature Science fund of Jiansu province. Methanol can be electrolyzed under high voltage, then ion may be react on cathode and anode. Carbon can be deposited on cathode (Ti alloy). DLC films can be deposited by changing technology, such as voltage, distance and temperature. Structure and morphology of DLC films deposited by liquid deposition are evaluated by Raman, XPS, FTIR and SEM. Influence of technology is also studied and optimum technology is determined. Properties of DLC films, such as coefficient of friction, antifriction, micro-hardness and adherence are examined. The blood-compatibility of DLC films is evaluated by dynamic clotting time, platelet assumption and hemolysis. Mechanism of liquid-deposition is suggested in light of electro-chemistry. There are some important conclusions.(1) A new method is developed to deposit DLC film on surface of Ti alloy by liquid-deposition. The optimum technology is as follows: voltage between 1650-1850v, distance between 8-1 0mm, temperature between 60-62℃ and time beyond 36h.(2) Blood-compatibility of DLC films deposited by liquid-deposition is evaluated for the first time. Based on three factors of kinetic clotting time, platelet consumption and hemolysis, blood-compatibility of DLC film is better than that of Ti alloy.(3) Structure of DLC films deposited by liquid-deposition is analyzed by Raman, XPS, FTIR and SEM for the first time. It is shown that these films are a:C-H films and hydrogen is combined with sp3 hybrid carbon. It also can be concluded that content of sp2 hybrid carbon increases in the vertical direction to surface. DLC films are made up of the round particles which diameter...
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