口腔用近β钛合金双层辉光离子渗氮改性后腐蚀性能的实验研究

Experimental study on the corrosion behavior of a type of oral near β-type titanium alloys modified with double glow plasma nitriding

目的 研究生物医用近β钛合金（Ti-3Zr-2Sn-3Mo-25Nb,TLM）双层辉光离子渗氮改性前后的电化学腐蚀性能,为TLM在口腔种植和修复的临床应用提供依据.方法 利用双层辉光离子渗氮技术对TLM试件表面进行渗氮改性处理.应用金相显微镜、扫描电镜、辉光放电光谱分析仪、X线衍射仪、显微硬度仪测试试件表面性能（显微硬度测试时分别在渗氮改性前后试件上选择5个点进行测量）;运用电化学测量系统分别测试并对比改性前后TLM在人工唾液中的电化学腐蚀性能.通过扫描电镜比较改性前后TLM表面形貌.结果 双层辉光离子渗氮技术可成功在TLM表面制备一层厚度为4～5 μm,致密、均匀的改性层,主要成分为Ti及Ti2N,且显微硬度由改性前的（236.8±5.4） HV 升至改性后的（871.8±5.2） HV;自腐蚀电压从-0.559 V升至-0.540 V,自腐蚀电流密度从2.091×10^-7 A/cm^2降低到7.188±10-8A/cm^2,交流阻抗值增大,扫描电镜下可见改性层腐蚀孔直径约10 μm,直径大小及数量较改性均有所减少.结论 TLM表面可成功进行渗氮改性,同时在人工唾液中改性后TLM的耐腐蚀性能较改性前有所提升.

Objective To study the electrochemical corrosion performance of a type of biomedical materials near beta titanium alloy（Ti-3Zr-2Sn-3Mo-25Nb, TLM） in artificial saliva before and after nitride changing, and to provide clinical basis for clinical application of titanium alloy TLM.Methods The double glow plasma alloying technology was used to nitride the surface of titanium alloy TLM.The surface properties of the modified layer were observed and tested by optical microscope, scanning electron microscope, glow discharge spectrum analyzer, X-ray diffraction and micro hardness tester.Then, electrochemical measurement system was used to test and compare titanium alloy TLM＇s electrochemical corrosion in artificial saliva before and after its surface change.Finally, the surface morphology of the original titanium alloy and the modified layer was compared by scanning electron microscope.Results By the technology of double glow plasma nitriding, the surface of the titanium alloy TLM had been successfully nitrided with a modified layer of 4-5 βm in thickness, uniform and compact.Its main compositions were Ti and Ti2N.The Microhardness of modified layer also had been improved from （236.8±5.4） to （871.8±5.2） HV.The self-corrosion potential in electrochemical corrosion tests had been increased from-0.559 V to-0.540 V,while the self-corrosion current density had been reduced from 2.091 ×10^-7 A/cm^2 to 7.188×10^-8 A/cm^2.Besides, alternating-current impedance（AC Impedance） had also been increased.With the scanning electron microscope, it＇s obvious that the diameter of corrosion holes on modified layer were approximately 10 βm.As to the diameter and number of corrosion holes on modified layer, they had been decreased comparing with the original titanium alloy.Conclusions The type of near beta titanium alloy TLM can construct a nitriding modified layer on its surface.Meanwhile, the performance of its anti-corrosion in artificial saliva has been improved, comparing to the original titanium alloy TLM.