张冬青，李壮，刘艳梅，王铁钢^*

(天津职业技术师范大学天津市高速切削与精密加工重点实验室 天津 300222)

摘要：AlCrSiN涂层具有较高的硬度与良好的高温稳定性，但在高速干切削工况下，涂层因温度过高磨损严重，导致其服役寿命大幅降低。为解决上述难题，通过掺杂Mo元素，切削过程中易形成MoO₃润滑相，可降低摩擦减少切削热的产生，提高涂层使用寿命。但Mo含量过高，会严重削弱涂层力学性能，服役过程中易发生破裂或剥落；若Mo含量过低，涂层减摩效果不明显。故本研究拟优化AlCrMoSiN涂层中Mo含量，采用高功率脉冲磁控溅射和脉冲直流磁控溅射复合技术，研制了一系列具有不同Mo含量的AlCrMoSiN涂层，通过改变CrMo靶溅射功率，调节涂层中Mo含量。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和高分辨透射电子显微镜(HRTEM)、纳米压痕仪、纳米划痕仪、高温摩擦磨损试验机等检测设备对涂层微观形貌、物相组成、力学性能、摩擦学行为进行表征。结果表明：随Mo含量的增加，AlCrMoSiN涂层的结晶度提高，晶粒尺寸增大；XRD衍射峰向大角度偏移，并在(111)和(200)晶面上择优取向明显，涂层中逐渐形成fcc-(Al,Cr,Mo)N固溶相为主的结构；涂层的硬度、弹性模量、H/E和H³/E^*2、摩擦系数均呈下降趋势；但磨损率呈上升趋势。当CrMo靶溅射功率为0.4 kW时，涂层中Mo含量达到21.3 at.%，此时涂层的特征值H/E和H³/E^*2最高，分别为0.059和0.052；临界载荷最高，为67.62 N；摩擦系数为0.54；在常温和高温800 ℃时的磨损率最低，分别为7.97×10^-4 µm³/N·µm和9.67×10^-4 μm³/N·µm，优于AlCrSiN涂层近一个量级。
 

Effect of Mo content on structure and properties of AlCrMoSiN coating
ZHANG Dongqing, LI Zhuang, LIU Yanmei, WANG Tiegang*
(Tianjin Key Laboratory of High Speed Cutting and Precision Manufacturing, Tianjin University of Technology and Education, Tianjin, 300222,China)

ABSTRACT: AlCrSiN coating has high hardness and good high temperature stability, but under the condition of high speed dry cutting, the coating is seriously worn due to excessive temperature, resulting in a significant reduction in its service life. In order to solve the above problems, by doping Mo element, MoO₃ lubricating phase is easy to form in the cutting process, which can reduce friction, reduce the generation of cutting heat and improve the service life of the coating. However, excessive Mo content will seriously weaken the mechanical properties of the coating, and it is easy to break or peel off during service. If the Mo content is too low, the anti-friction effect of the coating is not obvious. Therefore, this study intends to optimize the Mo content in AlCrMoSiN coating. A series of AlCrMoSiN coatings with different Mo content were developed by high power pulsed magnetron sputtering and pulsed DC magnetron sputtering. The Mo content in the coating was adjusted by changing the sputtering power of the CrMo target.The microstructure, phase composition, mechanical properties and tribological behavior of the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), nanoindentation, nanoscratch tester and high temperature friction and wear tester.The results show that with the increase of Mo content, the crystallinity and grain size of AlCrMoSiN coating increase. The XRD diffraction peak shifts to a large angle, and the preferred orientation is obvious on the (111) and (200) crystal planes. The structure of fcc-(Al,Cr,Mo)N solid solution phase is gradually formed in the coating. The hardness, elastic modulus, H/E, H³/E^*2 and friction coefficient of the coating decreased. But the wear rate is on the rise. When the sputtering power of CrMo target is 0.4 kW, the Mo content in the coating reaches 21.3 at.%, and the characteristic values H/E and H³/E^*2 of the coating are the highest, which are 0.059 and 0.052, respectively. The critical load is the highest, which is 67.62 N; the friction coefficient is 0.54; the lowest wear rate is 7.97×10^-4 µm³/N·µm at room temperature and 9.67×10^-4 μm³/N·µm at 800 ℃, which is nearly one order of magnitude better than that of AlCrSiN coating.