SYNTHESIS OF BONE THEN FILMS BY LASER ABLATION AND THEIR APPLICATIONS TO IMPLANT MATERIALS

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The ArF excimer laser deposition technique has been used to fabricate bioceramic hydroxyapatite (HAp) thin films. the target was the pressed pellet, that was the mixture of HAp (Ca/P=2.03) powder and P_2O_5 powder for the control the Ca/P ratio of HAp films. The bone and tooth were also used as target. The crystallized HAp films were fabricated using a after annealing method or in-situ growth method. In the case of former method, the films were deposited in vacuum in pure oxygen gas (pressure 0.4 mTorr) at substrate temperature 100ﾟC.The films were annealed for 1-10 hr at 300-550ﾟC under the oxygen+water vapor flow. The HAp films have been grown on various inorganic or organic substrates, such as Ti, Al_2O_3/Si (100) and SrTiO_3 (100) inorganic materials, and polymides (PI) and polytetrafluoroethylene (PTFE) organic materials. The mechanical properties of HAp films were examined using a dynamic ultra-micro hardness tester and an Instron testing machine. The dynamic hardness was obtained to be 390 for HAp film on Ti substrate. Also, the tensile bond strengths of HAp film on PI and PTFE were 9.8MPa and 0.4MPa, respectively. and that of HAp film on Ti was more than 54MPa. In the case of latter method, the HAp films were deposited in vacuum in pure oxygen+water vapors (pressure 100mTorr) at temperature 450-550ﾟC.The formation of c-axis oriented HAp films has been accomplished on sapphire (0001) substrate The biocompatibility of HAp films were also studied by in-vitro experiments. In this experiment, 3T3-E1 cells were used for osteoblastic cells attachment models. As a results, the cells were attached and proliferated on the Ti substrate. This result indicate that the HAp films with laser ablation were useful for the biocompatible coating material of implant.