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采用碱热处理+电沉积+碱热处理相结合的工艺,在Mg-4.0Zn-1.0Ca-0.6Zr合金板材表面制备羟基磷灰石(HA)涂层。利用X射线衍射和SEM对涂层的组织和形貌进行了分析,对合金板材及HA涂层板材在SBF溶液中的可降解性能进行了研究,结果表明:通过前碱热处理+电沉积+后碱热处理的方法在电沉积温度50℃,电压10 V条件下,在Mg-4.0Zn-1.0Ca-0.6Zr合金板材表面制备出了平整、致密的HA涂层,其Ca/P的比值(1.72)与人骨的(1.67)相近;HA涂层Mg-4.0Zn-1.0Ca-0.6Zr合金板材在SBF溶液腐蚀过程中,发现3 d时腐蚀液穿过HA涂层开始浸蚀基体。随着腐蚀时间的延长,部分点蚀的直径扩大,构成局部腐蚀;HA涂层Mg-4.0Zn-1.0Ca-0.6Zr合金板材在SBF溶液中的初始腐蚀速率低于未涂层的合金板材,其在SBF溶液中的初始pH值的变化低于未涂层的,随降解时间延长,pH变化幅度开始增大,10 d后pH值平均值约为9.2,随后逐步趋于稳定;HA涂层Mg-4.0Zn-1.0Ca-0.6Zr合金板材在SBF溶液中的初始自腐蚀电位与未涂层的相比正移200 mV以上,亦说明了其在SBF溶液中的初始腐蚀速率低于未涂层的,但是随着涂层的脱落将促使腐蚀速率增大。
Hydroxyapatite (HA) coating was prepared on the surface of Mg-4.0Zn-1.0Ca-0.6Zr alloy sheet by a combination of alkaline heat treatment and electrodeposition + alkali heat treatment. The microstructure and morphology of the coating were analyzed by X-ray diffraction and SEM. The degradability of the alloy plate and the HA coating plate in SBF solution was studied. The results showed that: after pre-alkali heat treatment + electrodeposition + Alkali-heat treatment A flat and dense HA coating was prepared on the surface of Mg-4.0Zn-1.0Ca-0.6Zr alloy sheet at a temperature of 50 ℃ and a voltage of 10 V. The Ca / P ratio (1.72 ) Was similar to that of human bone (1.67). During the corrosive process of SBF solution, the HA-coated Mg-4.0Zn-1.0Ca-0.6Zr alloy plate was found to attack the substrate through HA coating after 3 days. The corrosion rate of HA coating Mg-4.0Zn-1.0Ca-0.6Zr alloy sheet in SBF solution was lower than that of uncoated alloy sheet with the increase of corrosion time, The change of initial pH value in SBF solution was lower than that of uncoated solution. With the prolongation of degradation time, the change of pH value began to increase. After 10 days, the average value of pH value was about 9.2 and then stabilized gradually. HA coating The initial corrosion potential of Mg-4.0Zn-1.0Ca-0.6Zr alloy sheet in SBF solution was more than 200 mV positive compared with the uncoated one, indicating that the initial corrosion rate in SBF solution was lower than that of uncoated Layer, but with the coating off will promote the corrosion rate.