| Carbon/carbon(C/C) composite is a novel material developed in the new material field and has great prospect in bone repair fields due to excellent mechanical properties, especially elastic modulus close to that of human bones. However, C/C composite is bionert, and in order to endow it with osteoconductivity and osteoinductity, biomedical materials with bioactivity could be coated on it. In this paper, on the basis of the reviews on two respects: titanium-based bioactive modification and bone tissue response to carbon materials, the research work was focused on new preparation technologies, mechanism and bone response behaviors in vitro and in vivo of calcium phosphate (CP) coating deposited on chemical vapor infiltration(CVI) C/C composite, and the main contents were as followings:1. Aiming to biomimetic activation for bioinert C/C composites, a novel method for preparing biomimetic bioactive CP coating on C/C composite was put forward, namely, the surface of C/C composite was first grafted with functional groups containing calcium and phosphate elements by sonoelectrochemical method and then dipped into supersaturated calcium phosphate solution for a period of time to induce the growth of CP crystal. By this technology, bioactive octacalcium phosphate (OCP) coating has been successfully prepared on C/C composite. In addition, the formation and growth of OCP coating were also discussed.2. Combination of sonoelectrochemical modified method and electrocrystalliztion(EC) processing, a novel technology, named cathode sonoelectrodeposition(SED), was developed for preparation of CP coating on C/C composite. As compared with EC, this technique not only keeps the characterization of a non-line of sight, but also provides C/C composite with more homogenous, densified and improved adhesive coating. Moreover this technology is also a self-optimizing deposition process for C/C composite. The mechanism of CP deposition on C/C composite was explored by XRD, and Raman spectrometry. It was found that in essence this process electrically simulated CP growth on C/C surface despite the combination of sonoelectrochemical modification, sonochemical synthesis and electrocrystallization.3. The mechanism of the effect of ultrasonic on the formation of CP coating by SED was explored by the analysis of deposition kinetic of brushite coating on C/C composite. Our experimental results confirmed that ultrasonic provided CP deposition on C/C composite in electrolyte with a special condition, and didn't change the process of CP formation. Meantime, our experimental results also showed that the dependence of current density on induction time was in consistence with Sand expression and the introduction of ultrasonic to electrolyte could accelerate diffusion of OH' formed on C/C surface.4. By XRD, FTIR, SEM and EDAX, the effect of current density was investigated on morphology, composition, structure of brushite coating on C/C composite by SED, and It was found that the sizes of as-deposited particles decrease with increase in current density, and the coatings with plate-like (021), granular-like (111), and flower-like (220) morphology werefabricated at different current densities respectively. After the alkaline-heat treatment, the brushite coating was converted to HA coating and the morphologies were no significant difference. In addition, the effects of different conditions, such as temperature, pH value, concentration and current density et al, were also systemically investigated on morphology, composition, structure of CP coating; it was also found that nano-bone-like apatite could be directly formed on C/C composite by SED.5. In order to comprehend the essence of the formation of calcium phosphate (CP) coating on carbon/carbon composite by (SED), a simplified deposition model was put forward. In this model, the deposition procedure of calcium phosphate coating consisted of two steps: the first was the movement of ions containing P and Ca elements towards the C/C cathode by means of diffusion, and the second was the CP coating growth on the C/C surface modified as result of the sonoelectrochemical reaction. The relevant mathematical model and the experiments to identify the physical and mathematical models were given. It was confirmed that the models were reasonable and the procedure of CP coating formation by SED was mainly controlled by ion diffusion in the electrolyte. In addition, kinetics of HA and brushite deposition on C/C composite were given, and by application of phase transformation nucleus formation theory, the dependence of temperature on induction time was also explained.6. The response behaviors of CVIC/C composite and HA coating on CVIC/C composite were investigated to osteoblasts in vitro and thighbone tissue in vivo, the results showed that HA coating by SED could speed up the attachment, proliferation, differentiation and maturation of osteoblasts in vitro, and reduce the release of carbon particles and facilitate the osteo-integration between bone and C/C composite' with HA coating in vivo at initial implantation stage.
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