【作者】 范爱兰；

【导师】 唐宾；

【作者基本信息】 太原理工大学 ， 材料加工工程， 2003， 硕士

【摘要】 钛合金（例如Ti-6Al-4V），具有比强度高、热强性好、耐蚀及生物相容性好等优点，广泛应用于航空航天、化工、生物医疗领域，然而钛合金耐磨性差以及易发生粘着的缺点，限制了它的应用。如何解决这个问题，一直是人们所关注的课题。 现有许多表面工程技术被用来提高钛合金的抗磨性，同时又不影响钛合金的耐蚀性及生物相容性。硬质涂层、离子注入及离子氮化等技术可以明显改善钛合金在低载荷和低滑动速度下的摩擦性能，但采用上述技术在Ti-6Al-4V表面获得的表面改性层在冲击载荷的作用下，表面改性层易产生裂纹或剥离而失效。解决这个问题的方法之一是通过增加改性层的厚度来承受在滑动摩擦过程中高的剪切应力。然而利用硬质涂层、离子注入及离子氮化技术一方面很难获得较厚的改性层，另一方面增加改性层的厚度也可能导致残余应力增加，易造成改性层剥落。针对其它表面改性技术的局限，本文采用一种等离子表面改性技术—双层辉光离子渗金属技术，对Ti-6Al-4V合金进行表面Mo-N共渗改性研究。 本文采用双层辉光离子渗金属技术对钛合金Ti-6Al-4V表面进行Mo-N合金化处理，通过调整三种不同的氮氩比获得相应的表面扩散层，并对改性层的组织结构、电化学特性、摩擦学及腐蚀-磨损性能分别研究。 研究结果表明：氮氩比在一定程度上影响表面合金层的组织结构。热力学角度和动力学角度两方面研究表面改性层的电化学特性，并在相同的腐蚀条件下与Ti-6Al-4V基材的电化学性能进行对比，结果显示，Mo-N改性层自腐蚀电位均得到了提高，腐蚀速率与基材相比较未显现恶化倾向。在空气、NaCl及H₂SO₄等不同介质中，Mo-N改性层不仅显著降低了摩擦系数，而且耐磨性亦显著提高。更多还原

【Abstract】 Titanium and its alloys, such as Ti-6Al-4V, are widely applied to aerospace, chemical and bioengineering due to their high ratio of strength to weight, high temperature resistance, corrosion resistance and biocompatibility. However, their poor wear resistance and a tendency to galling are the major concerns to potential users.Numerous surface engineering technologies have been explored to enhance the wear resistance of the titanium alloys while maintaining their corrosion resistance and biocompatibility. Coating, plasma immersion ion implantation (PHI), and plasma nitriding are amongst the technologies explored. Whereas the wear resistance of Ti-6Al-4V alloy at low stresses and low velocities can be improved by the above techniques, cracking and debonding often occur at the modified layers at high sheer stresses. One of the solutions to the problems is increase the thickness of modified layers to withstand the high shear stresses during sliding wear. However, thick modified layers are difficultly obtained using coating, PHI, and plasma nitriding technologies. On the other hand, increasing thickness of the modified layers may result in an increase in residual stress and the risk of debonding. Therefore, a Mo-N modified layer was explored for the surface modification of Ti-6Al-4V alloy using an innovative plasma surface alloying technology. The objective of the study is to characterize the tribological properties of the thick, adhesive, and wear resistant surface modified layer obtained using this technology.In the paper, the double glow plasma surface alloying technique is carried out on titanium alloy Ti6A14V. The surface alloy layers were obtained with the three different ratio of N to Ar. The structure, electrochemical, wear and corrosive-wear behaviors of the surface alloy layers were investigated respectively.Results of the diffusion layer structure were investigated. It indicate that the surface alloy layer’s structure is affected by the ratio of N to Ar to a certain degree. In view of thermodynamics and kinetics, the electrochemical properties of the surface alloy layers were investigated and compared with that of TJ6A14V base material. Results indicate that self-corroding electric potentials is higher than that of Ti6A14V base material, and corrosion-rate to be similar or equivalent in experimental conditions. The wear and corrosive-wear behaviors’of the surface alloy layers were studied. The results show that these Mo-N diffusion layers not only significantly lowers the coefficient of friction, but also enhances the wear resistance of the titanium alloy in different solutions.更多还原