微量Ag元素对TiAlN涂层摩擦学性能的影响

采用电弧离子镀技术利用Ti₅₀Al₅₀、Ti₅₀Al₄₉Ag₁、Ti₅₀Al₄₅Ag₅合金靶沉积制备出了TiAlN及不同Ag含量的TiAlAgN涂层. 利用球-盘式摩擦磨损试验机研究了室温、200、400和600 ℃等温度下的摩擦学性能；通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)、显微硬度计、表面轮廓仪和划痕仪对磨损前后涂层的表面形貌、微观结构、硬度及涂层结合力进行了分析. 结果表明:TiAlN、TiAlAgN(Ag原子百分数0.12%)、TiAlAgN(Ag原子百分数0.30%)涂层的厚度分别为为4.18、5.31和4.69 μm，硬度分别为HV_0.2 2 049.4、HV_0.2 1 672.9、HV_0.2 1 398.5；TiAlN、TiAlAgN涂层的衍射峰位与面心立方的TiN相同，掺入Ag后TiAlN涂层的择优取向变为N(220)面. 三种涂层在不同温度下的磨损机理主要为黏着磨损与磨粒磨损. 室温时TiAlN涂层的摩擦系数比其他两种涂层要小约0.3，200 ℃时三种涂层的磨损率较大，400 ℃时掺Ag涂层的耐磨效果达到最佳. 此外，当Ag原子百分数在0.12%~0.30%范围时，随着Ag含量增加，涂层的结合力降低. 

Effect of Trace Ag on Tribological Properties of TiAlN coating

TiAlN and TiAlAgN coatings with different Ag contents were prepared by arc ion plating with Ti₅₀Al₅₀, Ti₅₀Al₄₉Ag₁, Ti₅₀Al₄₅Ag₅ alloy targets in this paper. The tribological properties were studied by using a ball-on-disk tribo-meter at room temperature, 200 ℃, 400 ℃ and 600 ℃.The surface morphology, microstructure, hardness and adhesion of the coatings before and after wear were determined by scanning electron microscope, X-ray diffraction, microhardness tester, surface profiler and scratch tester. The results showed that the thickness of TiAlN, TiAlAgN(0.12%Ag, atomic percentage), TiAlAgN(0.30%Ag, atomic percentage) coating was 4.18 μm, 5.31 μm and 4.69 μm. The hardness was HV_0.2 2 049.4, HV_0.2 1 672.9, HV_0.2 1 398.5, respectively. The diffraction peaks of TiAlN and TiAlAgN coatings were the same as those of FCC TiN, and the preferential orientation of N(220) for TiAlN coating was found after adding Ag. The wear mechanism of the three coatings at elevated temperatures was identified as adhesive wear and abrasive wear. At room temperature, the friction coefficient of TiAlN coating was about 0.3, which was lower than that of the other two coatings. The wear rate of the three coatings was higher at 200 ℃, and the best wear resistance was obtained at 400 ℃. In addition, as the Ag contents were between 0.12%~0.30%, the adhesion of the coating decreased.