氮等离子焰纯钛表面氮化

Pure titanium surface nitriding by nitrogen plasma flame

利用改造TIG焊枪通入N2+Ar混合气体产生氮等离子焰,在大气中直接加热纯钛试件,使基体表面的Ti元素与等离子焰中的N元素相互作用形成氮化层.主要研究了氮化温度和氮化时间对纯钛表面氮化层组织及性能的影响规律,得到了较佳氮化工艺参数.采用金相显微镜、扫描电镜和X射线衍射等检测方法,分析了氮化层的形成机理、表面及截面微观形貌,并测试了表面显微硬度及耐磨性.结果表明,氮化层主要由TiN相组成,组织均匀、致密,与基体为良好的冶金结合,有效地改善了纯钛基体的耐磨性.

A nitrogen plasma flame produced by a modified TIG welding torch was applied to heat the pure titanium specimens in the atmosphere directly and make them nitrided with the N2+Ar plasma gas mixture, so that the nitrided layer was obtained through the interaction between Ti element of the substrate surface and N element of the plasma flame. The changes of the microstructures and properties of the nitrided layers were mainly studied by changinvg the nitriding temperature and nitriding time. And the better nitriding processing parameters were obtained. The mechanism of the nitrided layers and their morphologies both surface and cross-section were investigated by optical microscopy, scanning electronic microscopy, X-ray diffraction and so forth. The surface micro-hardness and the wear resistance of the nitrided layers were tested as well. The experiment and analysis results showed that the nitrided layers were mainly composed of TiN phase. The homogeneous and dense nitrided layers were well metallurgically combined with the substrate. And also they can effectively improve the wear resistance of the pure titanium substrate.