SURFACE TREATMENT OF SHAPE MEMORY ALLOY APPLING TO SURGERY MATERIALS AND ITS EVALUATION

目的是将镍钛形状记忆合金应用于种植体材料。然而，它会经历点蚀。因此，采用等离子喷涂的方法在镍钛合金表面沉积了一层钛，但由于涂层的多孔性，加速了基体的点蚀。尝试用生物相容的聚合物树脂封闭喷涂层的气孔。在一系列的研究中，使用了自固型有机硅树脂、双液型环氧树脂和速凝型氰基丙烯树脂三种聚合物树脂作为密封剂。评价和讨论了它们在封闭气孔和保护孔蚀方面的作用。市售的有机硅树脂胶粘剂和环氧树脂胶粘剂的粘性都很高，无法渗透到多孔的钛层中。粘合剂需要用溶剂稀释。四氯化碳是有机硅树脂的最佳溶剂，丙酮是环氧树脂的最佳溶剂。超声波对稀释树脂胶粘剂的渗透有较好的效果。这似乎是因为毛孔中的空气很容易被去除。氰基丙烯树脂粘结剂的粘性较小，因此可以认为它不需要稀释。然而，即使氰基丙烯酸酯很容易渗透，它很快就会在到达钛层底部之前固化。因此，需要稀释以控制凝固。从电化学极化实验评价的结果来看，每种树脂达到钛层底部的最佳条件是：环氧树脂、氰基丙烯树脂和有机硅树脂。保护能力的不同似乎与水分子的吸收能力不同。作为另一种合金涂层技术，等离子镀四氟乙烷树脂也曾尝试过，但不能满足实际应用的需要。

The authors aim to apply Ni-Ti shape memory alloy as an implant material. However, it undergoes pitting corrosion. Thus, the surface of Ni-Ti alloy was coated with Ti by plasma spray, but as a result, the porous ti layr accelerates pitting corrosion of the substrate. The pores of the sprayd Ti layr was made attempt to be sealed with biocompatible polymer resins. In a series of this research, three polymer resins of self-solidified type silicone resin, two-liquid type epoxy resin and instantly-solidified type cyanoacryl resin were employed as a sealant. Their effect on sealing of pores and protection of pitting corrosion was evaluated and discussed. Both the commercial silicone resin adhesive and epoxy resin adhesive employed were so highly viscous that cannot penetrate into porous Ti layr as they are. Dilution of the adhesives by solvents were required. Carbon tetrachloride was the best solvent for silicone resin but acetone was the best for epoxy resin. Moreover, Supersonic wave gave a good effect on penetration of diluted resin adhesives. This seems to be because the air in the pores is easily removed. Cyanoacryl resin adheseiv is so less viscous that it can be considered that it does not need dilution. However, even if cyanoacrylate easily penetrates, it soon solidifies before reaching the bottom of the Ti layr. Therefore, dilution is required to control solidification. From the results of evaluation by electrochemicla polarization experiment, an optimum condition was obtained to reach the bottom of Ti layr for each resins but comparing each other protection abbility to pitting corrosion was ranked as epoxy resin>cyanoacryl resin>silicone resin. Difference in the protection ability seems to be stemed from that in absorbability of water molecules. As another technique for coating trhe alloy, plasma-plating of tetrafluoroethane resin was tried but it could not stand practical usage.