超声场下磷化时间对NiTi合金表面磷化膜形貌及性能的影响

Effects of Phosphating Time on Morphology and Properties of Phosphating Film on NiTi Alloy in Ultrasonic Field

目的通过表面改性处理来减小镍离子溢出对人体产生的危害,同时提高其力学及生物性能。方法采用超声磷化技术在镍钛合金表面制备磷化膜,研究磷化时间对NiTi合金表面磷化膜形貌及性能的影响,借助扫描电子显微镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)、摩擦磨损仪及电化学工作站等仪器对表层的形貌、结构、成分、耐腐蚀性、耐磨性、生物活性进行表征。结果超声磷化最优磷化时间为1 h,生成的磷化膜均匀、致密、完整,呈细小短棒状,其厚度约为17.5μm,自腐蚀电位由基材的-0.72 V提高到-0.3229 V,自腐蚀电流密度下降了2个数量级,摩擦系数稳定在0.12左右,相比于基材的0.50,降低了很多。磷化膜浸泡在SBF中30天后,成功吸附了细小、均匀、致密的类羟基磷灰石。结论超声磷化处理能明显改善镍钛合金的耐蚀性能、耐磨性能以及生物性能。

To reduce harm of nickel ion overflow on human body through modified treatment of surface and improve its mechanical and biological properties. Ultrasonic phosphating technology was used to prepare phosphating films on the surface of NiTi alloy. The effect of phosphating time on the morphology and properties of phosphating film was studied. Morphology, structure, composition, corrosion resistance, abrasive resistance and biological activity of the surface were studied by scanning electron microscope （SEM）, X ray diffracmeter （XRD）, energy dispersive spectroscopy （EDS）, friction/wear meter, electrochemical workstation, etc. The optimal phosphating time was 1 h; the phosphating film was uniform, compact and complete, and the thickness was about 17.5 μm. The corrosion potential increased from -0.72 V of the substrate to -0.3229 V and the corrosion current density decreased by 2 orders of magnitude. The friction coefficient was stable at around 0.12, reduced a lot when com-pared to 0.50 of the substrate. After being soaked in SBF for 30 days, the surface adsorbed fine and uniform and dense hydrox-yapatite successfully. Ultrasound phosphating treatment can improve corrosion resistance, wear resistance and biological properties of NiTi alloy significantly.