口腔种植手术器械用不锈钢钛改性低温离子渗氮组织和性能

Microstructure and properties of Ti-modified low temperature plasma nitrided stainless steel used in dental implant surgical instruments

对口腔种植手术器械用304奥氏体不锈钢进行低温钛改性离子渗氮处理,旨在保障其耐蚀性前提下,高效提高表面硬度和耐磨性。采用光学显微镜、扫描电镜、能谱分析仪、X射线粉末衍射仪、显微维氏硬度计及摩擦磨损测试仪等分别对试样截面显微组织、物相及成分、截面显微硬度、渗层耐磨性等进行测试与分析。结果表明,304奥氏体不锈钢钛改性低温离子渗氮效率比传统离子渗氮显著提升,420℃×4 h条件下,渗氮层厚度由常规离子渗氮的11.37μm增厚到48.32μm,即渗氮效率提高到常规离子渗氮的4倍以上。同时,低温钛改性离子渗氮处理后,304奥氏体不锈钢表面硬度与耐磨性大幅提高,表面硬度由常规离子渗氮的978 HV0.025提高到1350 HV0.025,磨损率由20.9μg/(N·m)降低至7.4μg/(N·m),下降约2/3。

Ti-modified low temperature plasma nitriding(LPNTi)was conducted for 304 austenitic stainless steel used for dental implant surgical instruments,and the goal was to effectively enhance the hardness and wear resistance without sacrifice of its corrosion resistance.Optical microscope,SEM,EDS,X-ray diffractometer(XRD),microhardness tester and friction and wear tester were used to investigate the microstructure and properties.The results show that the plasma nitriding efficiency can be remarkably improved by Ti-modification,which is more than 4 times of that by traditional low temperature plasma nitriding(LPN),with the thickness of nitrided layer increasing from 11.37μm by LPN to 48.32μm by LPNTi under the same nitriding condition of 420℃×4 h.Meanwhile,the surface hardness is significantly enhanced from 978 HV0.025 to 1350 HV0.025 by Ti-modification.The wear resistance is dramatically enhanced as well,with the mass wear rate decreasing from 20.9μg/(N·m)to 7.4μg/(N·m),decreasing about 2/3 by Ti-modification.