医用钛合金微弧氧化膜的制备及其生物适应性能

Preparation of Micro-Arc Oxidation Coating on Titanium Alloy and Evaluation of Its Biocompatibility

在钛及钛合金表面生成羟基磷灰石(HA)来制备生物材料是医学应用中亟待解决的问题。利用微弧氧化工艺在Ti合金表面制备了HA膜,研究了膜层在模拟体液中浸泡前后的形貌、相结构、Ca与P原子分数比,并分析了膜层在模拟体液中的降解和沉淀机制以及浸泡后的耐磨性。结果表明:膜层在模拟体液中随浸泡时间延长而逐渐变厚;浸泡20 d后膜层中HA晶粒发育完整,不定形相减少,表面Ca,P含量比下降至1.66,已接近人体骨骼标准;膜层在模拟体液中的降解和溶解有利于其与骨骼的结合;浸泡时模拟体液的pH值变化不大,说明膜层化学稳定性好,耐模拟体液腐蚀;在模拟体液中浸泡后膜层的摩擦系数随摩擦时间延长先升高后降低,耐磨性最终呈升高趋势。

Hydroxyapatite(HA)coating was prepared on the surface of Ti alloy by micro-arc oxidation.The morphology,phase structure and Ca/P ratio of resultant micro-arc oxidation coating before and after immersion in simulated body fluid were analyzed,and its degradation and precipitation mechanism in the simulated body fluid was explored.Moreover,the wear resistance of the micro-arc oxidation coating after immersion in the simulated body fluid was evaluated.Results indicate that the thickness of as-obtained micro-arc oxidation coating increases with extending immersion time.The micro-arc oxidation coating immersed for 20 d contained well developed HA grains and decreased contents of amorphous phases,with a decreased Ca/P ratio of 1.66.In the meantime,the degradation and dissolution of the micro-arc oxidation coating in the simulated body fluid were beneficial to strengthening its binding with bones.During the immersion process,the pH value of the simulated body fluid kept almost unchanged,which meant the micro-arc oxidation coating had good chemical stability and corrosion resistance against body fluid.Besides,the friction coefficient of the micro-arc oxidation coating after immersion in the simulated body fluid initially rose but later declined,and its wear resistance tended to increase.