TC4钛合金表面沉积TiCN涂层及其耐磨耐腐蚀性能研究

目的提高TC4钛合金的耐磨耐蚀性能。方法采用双阴极等离子溅射沉积技术在TC4合金表面制备了TiCN涂层。通过XRD表征了涂层的物相组成,并通过SEM表征了涂层的微观形貌。利用声发射划痕仪研究了涂层与基体的结合力,摩擦磨损试验机用于研究TiCN涂层的摩擦磨损性能。用电化学工作站在3.5%NaCl溶液中进行电化学实验。结果所沉积涂层均匀致密,无明显缺陷,涂层由外层厚度约为8μm的TiCN沉积层和其下约4μm厚的过渡层组成。TiCN涂层与TC4基体的结合强度比较高,其结合力达到66.4 N。室温条件下法向载荷相同时,TiCN涂层的磨痕宽度远小于TC4钛合金基体的磨痕宽度。TiCN涂层的比磨损率为(1~2)×10^-5 mm^3/(N·m),TC4钛合金的比磨损率为(2~4)×10^-4 mm^3/(N·m),TiCN涂层的比磨损率较TC4钛合金降低了1个数量级以上,并且对载荷的变化不敏感。TiCN涂层与TC4钛合金基体比较,具有更高的自腐蚀电位和更低的腐蚀电流密度,涂层的腐蚀电流密度为1.57×10^-9 A/cm^2,TC4钛合金的腐蚀电流密度为1.35×10^-8 A/cm^2,涂层的腐蚀电流密度较钛合金基体小1个数量级。TiCN涂层的EIS阻抗谱容抗弧值也较大。结论双阴极等离子溅射沉积TiCN涂层可以有效提高TC4钛合金的耐磨耐腐蚀性能。

TiCN Coating Deposited on TC4 Titanium Alloy and Its Wear and Corrosion Resistance

The work aims to improve the wear and corrosion resistance of TC4 titanium alloy.The titanium carbide nitride coating was prepared on the surface of TC4 alloy by double cathode plasma sputtering deposition.The phase composition of the coating was characterized by XRD,and the microstructure of the coating was characterized by SEM.The adhesion of the coating to the substrate was studied by an acoustic emission scratch tester.The friction and wear tester was used to study the friction and wear properties of the TiCN coating.Electrochemical experiments were carried out in 3.5wt.%NaCl solution with electrochemical workstation.The deposited coating was uniform and dense without obvious defects.The coating consisted of a TiCN deposit with an outer layer thickness of about 8μm and a transition layer of about 4μm thick below it.The TiCN coating had a higher bonding strength with the TC4 substrate and its binding force reached 66.4 N.The wear scar width of the TiCN coating was much smaller than that of the TC4 alloy substrate under the same normal load at room temperature.The specific wear rate of TiCN coating was about(1~2)×10^-5 mm^3/(N·m),and the specific wear rate of TC4 titanium alloy was about(2~4)×10^-4 mm^3/(N·m).The TiCN coating had a specific wear rate,an order of magnitude lower than that of the TC4 titanium alloy and insensitive to changes in load.The TiCN coating had a higher self-corrosion potential and a lower corrosion current density than the TC4 titanium alloy substrate.The corrosion current density of the coating and the TC4 titanium alloy was respectively 1.57×10^-9 A/cm^2 and 1.35×10^-8 A/cm^2.The corrosion current density of the coating was an order of magnitude lower than that of the titanium alloy substrate.The EIS impedance spectral capacitance of the TiCN coating was also large.TiCN coating deposited by double cathode plasma sputtering can effectively improve the wear and corrosion resistance of TC4 titanium alloy.