镍钛合金表面电沉积羟基磷灰石以及EDTA-2Na的影响

发布时间：2019-06-02 23:09

【摘要】：镍钛合金是一种由钛和镍元素等原子构成的合金，具有形状记忆特性和超弹性，在临床上可用于脊柱侧弯矫正和牙齿矫正，可用于制作血管支架、医用导线等。但是镍钛合金是一种金属材料，且镍本身对身体有毒性，材料生物相容性差。为了将镍钛合金优良的机械性能用于医学上，就要对其进行生物活化处理。近年来，羟基磷灰石的研究引起了人们广泛关注，它是脊椎动物骨骼无机成分，具有优良的生物活性，且可以通过体外化学合成，使得大量生产成为可能。但是羟基磷灰石机械性能差，不能用于承重部位。鉴于镍钛合金和羟基磷灰石各自具有的长处和不足，人们设想将两种材料结合在一起，以期充分发挥羟基磷灰石的生物活性和镍钛合金的机械性能。合成的方法有多种，像等离子体喷涂法、凝胶溶胶法、仿生矿化法和电化学沉积法等。电化学沉积法由于反应条件温和，周期短，条件易于控制的优点得到人们的重视。本文采用的方法就是电化学沉积法。本文首先对电化学沉积法的条件进行了探索，分析了电流密度、沉积时间、络合剂乙二胺四乙酸二钠（EDTA-2Na）对电化学沉积的影响，分析了阳极腐蚀、双氧水处理和碱热处理（NaOH）对于提高镍钛合金的生物活性的作用。实验结果表明：阳极腐蚀可以形成疏松多孔的形貌，有利于扩大材料的表面积，有利于羟基磷灰石的矿化；双氧水处理形成了氧化物层，在镍钛合金基底和羟基磷灰石涂层间形成了过渡层，减弱了热膨胀系数的差距；碱热处理在表面形成了能够诱导羟基磷灰石形核生长的钛酸钠（Na2TiO3）；电流密度为1mA/cm2为好，这时单个羟基磷灰石生长的较为充分，对镍钛合金基底的覆盖充分；电沉积时间为一小时为宜，此时单个羟基磷灰石生长充分，对基底的覆盖较好，没有出现结晶；电沉积液中EDTA-2Na的物质的量浓度在1.5~2.5×10-4mol/L为好，此时羟基磷灰石致密，对镍钛合金基底覆盖充分，羟基磷灰石间疏松，有间隙，末端盘绕，，这种结构有利于细胞伪足附着；EDTA-2Na的加入使得羟基磷灰石更为纤细、致密，它的形貌表现出末端出现聚拢；EDTA-2Na使得所得羟基磷灰石的羟基的峰更为明锐，并有效抑制了碳酸根的生长；EDTA-2Na使得羟基磷灰石生长的缓慢而均匀，在其他实验条件一致的情况下，对镍有比对钛更强的抑制作用；模拟生理液浸泡实验表明，仅仅经过化学抛光的镍钛合金表面仅仅有零星矿化，阳极腐蚀后出现较多的矿化，双氧水处理后矿化明显增多，EDTA-2Na的加入使得矿化更为均匀平滑，能谱图（EDS）表明EDTA-2Na的加入使得矿化速度变慢；成骨细胞能够在含有EDTA-2Na的羟基磷灰石涂层表面很好的粘附，说明含有EDTA-2Na的羟基磷灰石涂层具有好的生物活性；拉伸试验结果表明，EDTA-2Na的加入使得羟基磷灰石与镍钛合金基底的结合强度提高了一倍；腐蚀实验表明EDTA-2Na的加入能提高涂层的耐腐蚀性；XRD结果表明EDTA-2Na促使羟基磷灰石沿c轴择优生长。
[Abstract]:The nickel-titanium alloy is an alloy made of atoms such as titanium and nickel elements, has shape memory property and super-elasticity, can be clinically used for scoliosis correction and tooth correction, and can be used for manufacturing a vascular stent, a medical wire, and the like. However, that nickel-titanium alloy is a metal material, and the nickel itself is toxic to the body, and the biocompatibility of the material is poor. In order to use the excellent mechanical properties of the nickel-titanium alloy for medical use, it is subject to a biological activation treatment. In recent years, the research of hydroxyapatite has attracted a wide range of attention, which is an inorganic component of a vertebrate bone, has excellent biological activity, and can be chemically synthesized in vitro, so that a large amount of production becomes possible. However, that mechanical property of the hydroxyapatite cannot be used for the load-bearing part. In view of the advantages and disadvantages of the nickel-titanium alloy and the hydroxyapatite, it is envisaged that the two materials are combined to give full play to the biological activity of the hydroxyapatite and the mechanical properties of the nickel-titanium alloy. There are many methods for synthesis, such as plasma spraying, gel sol, biomimetic mineralization and electrochemical deposition. The electrochemical deposition method has the advantages of mild reaction conditions, short period and easy control of conditions. The method adopted in this paper is the electrochemical deposition method. In this paper, the conditions of the electrochemical deposition method are explored, and the influence of current density, deposition time, complexing agent ethylenediaminetetraacetic acid disodium (EDTA-2Na) on the electrochemical deposition is analyzed, and the corrosion of the anode is analyzed. To improve the biological activity of nickel-titanium alloy by etching, hydrogen peroxide treatment and alkali heat treatment (NaOH) The experimental results show that the corrosion of the anode can form a loose and porous morphology, which is beneficial to the surface area of the material, and is beneficial to the mineralization of the hydroxyapatite. The treatment of the hydrogen peroxide forms an oxide layer, and a transition is formed between the nickel-titanium alloy substrate and the hydroxyapatite coating. And the current density is 1 mA/ cm2. At this time, the growth of the single hydroxyapatite is sufficient, and the covering and filling of the nickel-titanium alloy substrate are carried out. And the concentration of the EDTA-2Na in the electrodeposition solution is between 1.5 and 2.5 to 10-4mol/ L, at the time, the hydroxyapatite is compact and the nickel-titanium alloy base is covered and filled. The hydroxyapatite is more slender and dense with the addition of EDTA-2Na, and the morphology of the hydroxyapatite is more slender and dense, and the appearance of the hydroxyapatite is more and more dense, and the peak of the hydroxyl group of the obtained hydroxyapatite is more clear by the EDTA-2Na. The growth of the carbonate is effectively inhibited, the growth of the carbonate is effectively inhibited, the growth of the hydroxyapatite is slow and uniform by the EDTA-2Na, and the inhibition effect on the nickel is stronger than that of the titanium under the condition that other experimental conditions are consistent; and the experimental table for soaking the physiological fluid is simulated. It is clear that only the surface of the chemically polished nickel-titanium alloy is only sporadically mineralized, and after the corrosion of the anode, the mineralization is more and the mineralization is obviously increased. The addition of the EDTA-2Na makes the mineralization more uniform and smooth, and the energy spectrum graph (EDS) shows that the addition of the EDTA-2Na makes the mineralization speed change. The results of the tensile test show that the bonding strength of the hydroxyapatite and the nickel-titanium alloy substrate is improved by the addition of the EDTA-2Na. The results show that the addition of EDTA-2Na can improve the corrosion resistance of the coating. The results show that the EDTA-2Na promotes the preferential growth of the hydroxyapatite along the c-axis.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318.08

【参考文献】