NaOH浓度对NiTi形状记忆合金表面类骨磷灰石形成的影响

EFFECT OF NaOH CONCENTRATION ON FORMATION OF BONE-LIKE APATITE LAYER ON NiTi SHAPE MEMORY ALLOY

研究了不同浓度NaOH对NiTi形状记忆合金在模拟体液(SBF)中诱导磷灰石沉积的影响.用XRD,ESEM,FTIR及XPS等分析了碱处理前后试样表面的结构、形貌、基团和组元化合价的变化.结果表明,经1 mol/L NaoH溶液处理的NiTi合金因为钛酸钠的生成而具有较高的生物活性,在SBF中浸泡3 d后自然沉积含CO32-的类骨磷灰石,而且原子吸收光谱分析其在Hank’s溶液中的镍离子溶出量最少.随着碱处理浓度的提高,NiTi合金表面除钛酸钠外,还有镍酸钠生成,使磷灰石形核的孕育期加长,在Hank’s溶液中的镍离子溶出量也明显增加.

The effect of different concentration NaOH aqueous solution on induced deposition of apatite layer on NiTi shape memory alloy in SBF was mesured. The morphology, phases, groups and valency change of element on the surface of chemically treated NiTi before and after soaking in SBF were analyzed by XRD, ESEM and X-ray photoelectron spectroscopy. The results show that the surface of NiTi treated by 1 mol/L NaOH aqueous solution exhibit a higher bioactivity because of formation of sodium titanate. The treated sample can form CO32- containing apatite layer after soaking in SBF for 3 d and reveal relatively little amount of Ni3+ ions releaseing in Hank's solution. With increasing NaOH concentration, not only sodium titanate but also sodium nickate forms on the surface of treated NiTi alloy, which increases incubation period of forming apatite nucleation on it. At the same time, Ni3+ ions releasing from NiTi treated with 5 mol/L NaOH in Hank's solution greatly increase.