pH值和缓冲剂对水热电化学沉积HA/TiO_2涂层的影响

Influence of pH value and slow granule on HA/TiO_2 coatings deposited by hydrothermal-electrochemical method

以微弧氧化后的钛合金为基体,采用水热电化学法制备了 HA/TiO 2涂层.利用 SEM、XRD 对涂层的表面形貌、物相组成进行了表征分析,通过 pH 微探针原位探测电极/电解液界面 pH 值的变化,研究了pH 值和缓冲剂对水热电化学沉积 HA/TiO 2涂层的影响.研究结果表明,微弧氧化膜有利于水热电化学沉积 HA,得到的 HA 晶体分布均匀、致密.当电解液pH 值在2~8时,pH 值升高有利于提高水热电化学沉积 HA 的结晶度,并促使 HA 沿（002）晶面生长.在水热电化学沉积 HA 过程中,电极表面的 pH 值随沉积时间的增加先升高后逐渐降低；而溶液中的 pH值随沉积时间的增加逐渐降低.pH 值和缓冲剂对涂层 HA 晶体形貌有明显影响,加入缓冲剂后得到的HA 晶体端面呈六边形棒状结构,晶体表面光滑、结晶完整.

Using titanium alloy after micro-arc oxidation as substrate,HA/TiO 2 coatings were prepared by hy-drothermal-electrochemical method.The morphologies and phase compositions of coatings were characterized by means of SEM and XRD,and the variation of pH value of electrode/electrolyte was measured by means of pH microprobe;in this way,the influences of pH value and slow granule on HA/TiO 2 coatings deposited by hydro-thermal-electrochemical method were investigated.The results show that micro-arc oxidation coatings contrib-ute to HA deposited by hydrothermal-electrochemical method and HA crystals are well-distributed and densified in the coatings.When the pH value was within the range of 2 to 8,the increasing of the pH value contributes to HA crystals with high crystallinity and the growth of HA along the crystallographic plane （002）.During the process of depositing HA by hydrothermal-electrochemical method ,pH value on the surface of electrode increa-ses at first and then decreases with the deposition time,while pH value of electrolyte decreases with the deposi-tion time.pH value and slow granule have obvious influences on the morphologies of HA crystals.HA crystals prepared in the electrolyte containing slow granule are rods in shape,the edge face of rod was a defined flat hex-agon and the surface of the crystal was smooth,and HA crystals are well-crystallized.