目的 研究SiO2含量对钛合金表面激光熔覆梯度生物陶瓷涂层生物活性的影响。方法 利用激光熔覆技术，采用梯度成分设计思想，固定涂层中稀土氧化物La2O3的添加量，在钛合金TC4表面制备了掺杂不同含量SiO2的梯度生物陶瓷涂层。采用金相显微镜（OM）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）、噻唑蓝（MTT）及荧光素双醋酸酯（FDA）染色等测试手段，研究了SiO2含量对激光熔覆制备梯度涂层的组织结构和生物活性的影响。结果 SiO2在激光熔覆过程中可以降低梯度生物陶瓷涂层的开裂敏感性，并起到细化晶粒的作用。当SiO2掺杂量为2.5%时，激光熔覆过程中诱导合成的HA+CaTiO3数量最大；当SiO2掺杂量为7.5%时，模拟体液（SBF）实验表明，涂层的矿化沉积能力最强。MTT测试表明，SiO2掺杂量为7.5%的涂层细胞增殖数量的OD值最大，细胞能够紧贴涂层表面生长。FDA染色分析表明，SiO2掺杂量为7.5%的涂层上细胞数量最多，且分布均匀。结论 SiO2掺杂量深刻影响着生物活性陶瓷相HA和Ca2SiO4数量，进而影响生物陶瓷涂层的生物活性。SiO2掺杂量为7.5%的涂层具有最佳的生物相容性及生物活性。

The work aims to study the effect of SiO2 content on the bioactivity of laser cladding gradient bioceramic coating on the titanium alloy. The coatings doped with different contents of SiO2 were fabricated on TC4 by laser cladding technology and design idea of gradient composition, with the fixed amount of rare earth oxide La2O3 in the coating. The effect of SiO2 content on the structure and bioactivity of laser cladding gradient coating was studied with OM, XRD, SEM, MTT and FDA. SiO2 could reduce the cracking sensitivity of the gradient bioceramic coating during the laser cladding and refine the grains. The coating with 2.5% SiO2 induced the most amount of HA+CaTiO3 during the laser cladding. The coating with 7.5% SiO2 demonstrated the strongest ability of mineralization and deposition in the simulated body fluid (SBF). The MTT test showed that the OD value of the proliferation number of cells in the coating with 7.5% SiO2 was the highest, and the cells could grow close to the coating surface. FDA staining analysis showed that the coating with 7.5% SiO2 had the largest number of cells and the cells were distributed evenly. The doping amount of SiO2 profoundly affects the amount of bioactive ceramic phase HA and Ca2SiO4, and further influences the bioactivity of bioceramic coating. The coating with 7.5% SiO2 possesses the best biocompatibility and bioactivity.