掺杂低含量SiO2对激光熔覆CaP生物陶瓷涂层性能的影响

为提高医用TC4钛合金表面熔覆羟基磷灰石（HA）涂层的植入稳定性和生物活性，采用激光熔覆方法制备出不同含硅量的CaP生物陶瓷涂层。利用扫描电子显微镜（SEM）和X射线衍射仪（XRD）表征了熔覆层组织形貌和物相组成。结果表明:添加SiO2（1wt.%、3wt.%）后形成Ca2SiO4相，熔覆层中部组织细化。通过电化学腐蚀和体外SBF浸泡实验研究了SiO2含量对涂层耐腐蚀性和生物活性的影响。电化学腐蚀结果表明:随着SiO2含量的增大，涂层表面腐蚀电流密度逐渐减小；体外SBF浸泡结果表明:添加SiO2可以加快涂层表面类骨磷灰石的形成，其中，添加SiO2为1wt.%时涂层表面类骨磷灰石呈均匀分布。因此，低含量SiO2可以提高生物陶瓷涂层的耐腐蚀性和生物活性。

Effects of doping low-content SiO2 on properties of laser cladding CaP bioceramic coatings

To improve the implantation stability and biological activity of the hydroxyapatite(HA) coating on the surface of medical TC4 titanium alloy, CaP bioceramic coating with different silicon contents were prepared by laser cladding method. Scanning electron microscopy(SEM) and X-ray diffractometry(XRD) were used to characterize the morphology and phase composition of the cladding layer. The results showed that the Ca2SiO4 phase was formed and the microstructure of the middle zone of the cladding layer was refined after adding SiO2(1wt.%, 3wt.%). The effects of SiO2 content on the corrosion resistance and bioactivity of the coating were investigated by electrochemical corrosion and in vitro SBF immersion experiments. Electrochemical corrosion results showed that the corrosion current density of the coating surface decreased with the increase of SiO2 content; The results of SBF soaking in vitro showed that the addition of SiO2 could accelerate the formation of bone-like apatite on the surface of the coating. When the content SiO2 was 1 wt.%, the surface of the coating-like bone apatite was uniformly distributed. Therefore, low-content SiO2 can improve the corrosion resistance and bioactivity of bioceramic coatings.