不動態皮膜を生成させたTiNi形状記憶合金の腐食疲労寿命

抄録

In this study, we enhanced the corrosion fatigue life of a TiNi shape memory alloy wire using a thermal nitridation treatment technique that can generated a passive film on the wire surface. We performed the following procedure for thermal nitridation treatment. First, the as-received material with an oxide film was mechanically polished to remove the film using an abrasive paper and a buffing compound. Second, the material was heat-treated in a furnace filled with a pure nitrogen gas for 1 h at 673 K. Subsequently, the material was allowed to cool in the furnace. The results obtained by this study are summarized as follows: (1) The corrosion resistance of the thermal nitrided material is much better than those of the normal heat treated and the polished material. (2) The fatigue life of the thermal nitrided material is not influenced by environment especially in the low-strain region.