不同w_(Ca)/w_(P)对宽带激光熔覆生物陶瓷涂层性能的影响

目的对不同w_(Ca)/w_(P)的宽带激光熔覆生物陶瓷涂层性能进行研究,探究w_(Ca)/w_(P)对涂层硬度、生物相容性及生物活性的影响规律,寻求最优试验参数,为以后制备性能优良的涂层提供参考。方法运用梯度设计思想,采用宽带激光熔覆技术,在钛合金表面分别制备w_(Ca)/w_(P)为1.35、1.40、1.45的梯度生物陶瓷涂层。利用X射线衍射仪(XRD)、扫描电镜(SEM)、金相显微镜、显微硬度仪、模拟体液浸泡试验、体外细胞试验,研究不同w_(Ca)/w_(P)对生物陶瓷涂层组织结构、生物相容性以及生物活性的影响。结果XRD结果表明,涂层主要由CaTiO_(3)、HA、Ca_(2)SiO_(4)、CaO、TCP等相组成。硬度测试表明,w_(Ca)/w_(P)=1.45的涂层平均显微硬度最高,而w_(Ca)/w_(P)=1.35的涂层平均硬度最低。体外细胞试验表明,所有涂层上的MG63分布均匀,细胞形态良好,w_(Ca)/w_(P)=1.40的涂层上的OD值增长较快,共同培养至第5天时,测得的OD值远高于其他涂层,相较于第1天的OD值增加最多。SBF浸泡试验表明,3种w_(Ca)/w_(P)的陶瓷涂层都在表面覆盖了类骨磷灰石,w_(Ca)/w_(P)=1.40的涂层,经浸泡后表面覆盖了最多的类骨磷灰石。观察细胞生长形态,细胞的许多丝状伪足紧贴在涂层上,使得细胞可以粘附在涂层上并生长,呈现出正常的梭形形态,具备较完整的细胞膜,w_(Ca)/w_(P)=1.40的涂层上粘附的细胞数量更多、分布更为均匀。结论当w_(Ca)/w_(P)=1.40时,Ca-P生物陶瓷涂层不仅拥有良好的生物矿化能力,能够形成更多类骨磷灰石,而且涂层上增殖吸附的细胞数量最多,涂层表现出良好的生物相容性和生物活性。

Formation characteristic of Ca-P coatings on magnesium alloy surface

A chemical method was used to deposit dicalcium phosphate dehydrate coatings on AZ91 magnesium alloy. The aim was to improve the biodegradation behavior of magnesium alloy in a simulated body fluid. The microstructures of the coating before and after immersion in the simulated body fluid were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD） The results indicated that the dicalcium phosphate dehydrate coatings exhibited two morphologies during the pre-calcification process. The titration speed of the pre-calcification process had great influence on the morphologies of the pre-calcification coatings. As the soaking time increased, the diffraction peaks of dicalcium phosphate dehydrate disappeared and hydroxyapatite precipitated on the coated substrate surfaces. This indicates the dissolution of dicalcium phosphate dehydrate during the immersion process. The structures of the dicalcium phosphate dehydrate coatings and the formation mechanisms of the hydroxyapatite coatings were investigated in detail.