氧化钛涂层对医用镁合金降解行为的影响

Effects of TiO_2 Coating on the Degradation Behaviors of Biomedical Mg Alloys

采用直流磁控溅射法在医用Mg-Zn-Y-Nd合金表面制备氧化钛涂层,研究了氧化钛涂层对镁合金在Kokubo’s模拟体液(SBF)中的降解速率和降解行为的影响。结果表明,镁合金经过氧化钛涂层改性前后的降解速率分别为1.39mm/y和0.61mm/y,氧化钛涂层在减缓镁合金基体降解速率的同时也提高了基体降解的均匀程度。在SBF中浸泡24h后氧化钛涂层基本维持原貌,镁合金基体未发生降解,浸泡72h后SBF可穿透涂层到达基体,使基体降解并产生氢气,导致涂层出现微小的突起,微米级的氧化钛碎片开始脱落。浸泡336h后,涂层由整体状分裂成离散状,并粘附在基体表面,减轻了Cl^-离子对基体的侵蚀作用。

TiO2 coating was prepared on biomedical Mg-Zn-Y-Nd alloys by DC magnetron sputtering.Effects of TiO2 coating on the degradation rate and degradation behavior of magnesium alloys were investigated in Kokubo＇s simulated body fluid（SBF）.The results show that the degradation rate of Mg-ZnY-Nd alloys is 1.39mm/y and 0.61mm/y,respectively,before and after surface modification treatment by the TiO2 coating.The degradation uniformity of Mg-Zn-Y-Nd alloys is improved significantly as a result of the protection of TiO2 coating.The change of TiO2 coating after 24 himmersion in simulated body fluid is absent,and the Mg alloy substrate is not degraded in this period.Up to 72 himmersion,the TiO2 coating is destroyed partly due to the generation of hydrogen and other degradation products,and the TiO2 coating began to be peeled from substrate.Most of TiO2 fragments can remain on the surface of substrate after 336 h,leading to a slower degradation of magnesium alloy.