NiTi合金表面类金刚石膜的表面特征和腐蚀行为

采用等离子浸没离子注入和沉积（PIIID）法以C2H2为等离子源对NiTi合金进行表面改性。利用Raman光谱分析膜层结构。采用原子力显微镜和纳米压痕分析涂层前后NiTi的表面形貌和力学性能。利用电化学测试、扫描电镜和原子吸收光谱测试涂层前后基体的耐腐蚀性和Ni离子析出。结果表明：NiTi合金表面的膜层是类金刚石（DLC）；经过PIIID处理后，基体表面的粗糙度降低；纳米硬度得到提高；耐腐蚀性能获得明显改善；Ni离子析出得到有效的抑制。

Surface Characteristics and Corrosion Behavior of DLC Film on NiTi Alloys

Diamond-like carbon(DLC) films were fabricated on NiTi alloys using plasma immersion ion implantation and deposition(PIIID).The surface morphology and roughness were analyzed by atomic force microscopy(AFM).The film microstructure and hardness were characterized by Raman scattering spectroscopy and nano-indentation system,respectively.The corrosion resistance in Hank's solution was evaluated by mean of potentiodynamic polarization techniques.The surface morphology of the samples was observed using scanning electron microscopy(SEM) after potentiodynamic polarization tests.The Ni ions release from the NiTi alloys was measured by atomic absorption spectroscopy(AAS).It is shown that the roughness and hardness of the NiTi alloys is reduced and increased by DLC film,respectively.The DLC films markedly improve the corrosion resistance of the NiTi alloys and effectively prevent the Ni ions dissolution from the substrate.