NiTi合金激光熔凝处理及其生物腐蚀性能研究  

Laser Melting Treatment on NiTi Alloy and Its Biological Corrosion Properties

作　　者：仇安 陈慧 宋婕 程学进[1] 丁红燕[1,2] 周广宏 QIU An;CHEN Hui;SONG Jie;CHENG Xue-jin;DING Hong-yan;ZHOU Guang-hong(Huaiyin Institute of Technology,Jiangsu Huaian 223003,China;Suqian University,Jiangsu Suqian 223800,China)

机构地区：[1]淮阴工学院,江苏淮安223003 [2]宿迁学院,江苏宿迁223800

出　　处：《表面技术》2023年第1期364-371,420,共9页Surface Technology

基　　金：国家自然科学基金项目(51875231)。

摘　　要：目的通过对NiTi合金表面进行激光熔凝处理,从而提高Ni Ti合金的耐腐蚀性能。方法利用紫外激光器对NiTi合金进行表面熔凝处理,借助扫描电子显微镜(SEM)、光学显微镜(OM)、能量色散X射线光谱仪(EDX)和X射线衍射仪(XRD)等技术手段,研究了激光熔凝处理前后Ni Ti合金的表面显微组织、成分和相结构。测试了激光熔凝处理前后NiTi合金表面与模拟体液(SBF)的接触角、熔凝层的显微硬度等表面性能。通过全浸腐蚀试验和电化学测试,研究了熔凝层在SBF溶液中的生物腐蚀性能,并分析了腐蚀机理。结果NiTi合金经过激光熔凝处理后,在合金的表层形成了厚度为90~150μm的熔凝层,熔凝层主要由TiO_(2)、β相以及少量的Ti O相组成。合金表面的平均显微硬度提高了153~279HV,合金的表面接触角增大,由亲水性转为疏水性。相较于未处理的样品,熔凝处理后的样品在SBF溶液中的腐蚀电位分别正移了435 mV和413 mV,腐蚀电流密度分别下降了83%、62%左右。熔凝处理后的样品在SBF溶液浸泡168 h后,SBF溶液中的Ni2+浓度下降了约1/3。结论以适当的激光加工参数对NiTi合金进行激光熔凝处理,可在NiTi合金表面形成致密的氧化膜,这层氧化膜和熔凝层可以有效地抑制NiTi合金在SBF溶液中的点腐蚀行为。NiTi alloy with equal atomic ratio has been widely used in biomedical field because of its excellent mechanical properties and shape memory effect.However,NiTi alloy can be corroded and released harmful Ni2+ions in human body.In this paper,laser melting was conducted on the surface of the NiTi alloy to enhance the corrosion resistance in simulated body fluid(SBF).The microstructure,phase structure of NiTi alloy modified by laser melting treatment with various process parameters,as well as the biological corrosion properties of the melted layer in SBF solution were studied.The surface physical properties of the molten layer,such as contact angle and hardness were also tested.The NiTi alloy specimens were cut into the size of 10 mm×10 mm×2 mm by wire electrical discharge machining,polished by sandpaper,and then cleaned in deionization water.Laser melting was performed on the surface of the NiTi alloy specimens by Diode laser pumped ultraviolet laser(MP101).Microstructure and corrosion morphology were observed by using optical microscope(OM,AxioImager A2)and scanning electron microscope(SEM,FEI Quanta 250)with an Oxford Instrument INCA EDS analyser capability.The EDS analysis has been performed with an acceleration voltage of 10 keV and Cu calibration.The water contact was tested using an angle measuring instrument(DSA20).The surface hardness of the specimens was measured by a Vickers micro-hardness tester(HV1000).The phase structure of the specimens was analyzed by X-ray diffractometer(XRD,D8 Discover).The specimens were sealed with epoxy resin,exposing a surface area of 1 cm^(2)and immersed in SBF solution at 37℃for 168 h for the corrosion test.The concentration of Ni2+ions in SBF solution was measured by inductively coupled plasma emission spectrometer(ICP,Optima 7000 DV)with 0.1 mg/L Ni standard solution.The electrochemical experiment was carried out using electrochemical workstation(CHI 660D)in SBF solution at 37℃.A three-electrode system was adopted,in which the specimen was the working electrode,the pla

关 键 词：NITI合金 显微组织 激光熔凝 熔凝层 生物腐蚀 氧化膜 

分 类 号：V261.8[航空宇航科学与技术—航空宇航制造工程] TG174[金属学及工艺—金属表面处理]