水热处理后TC4钛合金微弧氧化涂层的润湿性和电化学性能分析

针对TC4钛合金耐腐蚀性偏低、生物相容性差等问题,本试验利用微弧氧化(MAO)技术在TC4钛合金表面制备陶瓷涂层,结合水热合成技术在TC4钛合金涂层中引入具有生物活性的羟基磷灰石层,探究水热合成液浓度变化对TC4钛合金涂层的润湿性能和电化学行为的影响。利用XRD、SEM、润湿角测量仪、激光共聚焦显微镜以及电化学工作站等对TC4钛合金MAO涂层的相组成、表面形貌、润湿角、表面粗糙度、电化学性能等进行表征。研究结果表明:随着水热合成液浓度增加,TC4钛合金MAO涂层中金红石相TiO_2含量有所提高,羟基磷灰石(HA)相含量逐渐增加。水热合成液浓度的变化对TC4钛合金MAO涂层表面粗糙度的影响不大,粗糙度在1~2μm范围内。在水热合成处理后,TC4钛合金涂层的极化曲线会向正电位方向移动,腐蚀电位增加,腐蚀电流密度降低,降低幅度约为一个数量级。

Analysis on wettability and electrochemical properties of TC4 titanium alloy micro-arc oxidation coating after hydrothermal treatment

With respect to the low corrosiveness and poor biocompatibility problems of TC4 titanium alloy,the ceramic coating of TC4 titanium alloy was fabricated by micro-arc oxidation(MAO)technology in this test,and the bioactive hydroxylapatite layer was introduced into TC4 titanium alloy coating by means of hydrothermal synthesis technology.The influence of hydrothermal synthesis solution concentration change on the wettability and electrochemical behavior of TC4 titanium alloy coating was investigated.The phase composition,surface morphology,wetting angle,surface roughness and electrochemical properties of TC4 titanium alloy MAO coating were characterized by XRD,SEM,wetting angle measuring instrument,laser confocal microscope and electrochemical workstation.The study results showed that with the increase of hydrothermal synthesis solution concentration,the content of rutile phase TiO2 in TC4 titanium alloy MAO coating was enhanced and the content of hydroxyapatite phase was gradually increased.The concentration change of hydrothermal synthesis solution had little effect on the surface roughness of TC4 titanium alloy MAO coating,which was within 1~2μm.After hydrothermal synthesis treatment,the polarization curve of TC4 titanium alloy coating moved towards the positive potential direction,the corrosion potential increased and the corrosion current density decreased by an order of magnitude.