Abstract—

Nanoindentation at temperatures of 23 and 150°C is used to study the coating of molybdenum disulfide doped with silver and calcium fluoride. The Nanoscan-4D scanning nanohardness tester was used for the experiments. A method is presented for determining the elastic properties of a coating from elastic indentation curves, taking into account the real shape of the indenter head, which is determined by optical profilometry. The elasticity modulus of the coating is determined based on the exact solution of the contact problem for a two-layered elastic foundation, taking into account the calculated compliance of the measurement system. Newton’s method is used for the inverse problem solution. The input parameters of the problem, in addition to the geometry of the indenter head and the load, are the elastic properties of the head and substrate materials. The elastic type of indentation was provided at maximal load of 10 mN for both temperatures. The loading–unloading curves at room temperature and at 150°C turned out to be close (within the experimental error), which proves the stability of the elastic properties in the considered temperature range. The calculated elastic modulus of the coating was 326 GPa. Using the same device, equipped with a lateral force sensor, the sliding friction coefficient of the coating was determined under different loads (5, 10, and 20 mN). Such a study can be considered as a physical model of the contact of the coating with a single asperity. The experiments were carried out on straight tracks 1 mm long at a speed of 11 µm/s. It is shown that the coatings are antifrictional (with friction coefficients in the range 0.033—0.078). The coefficient of friction increases with increasing load, which may be due to the dissipation of energy for plastic deformation of the coating material at relatively high loads. The conclusion about the presence of plastic deformation is based on the results of optical profilometry, which showed plastically deformed and pushed material along the edges of the friction track under relatively high loads. At low loads, this phenomenon is not observed. This coating can be used in sliding friction units that require one or two applications with a low friction coefficient.

中文翻译：

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微纳米级二硫化钼纳米涂层的弹性和摩擦性能

摘要-

使用 23 和 150°C 温度下的纳米压痕研究了掺杂银和氟化钙的二硫化钼涂层。实验采用Nanoscan-4D扫描纳米硬度计。提出了一种根据弹性压痕曲线确定涂层弹性性能的方法，同时考虑到压头的真实形状（通过光学轮廓测定法确定）。涂层的弹性模量是根据两层弹性基础接触问题的精确解来确定的，同时考虑到测量系统的计算柔度。牛顿法用于逆问题的求解。问题的输入参数除了压头的几何形状和载荷之外，还有压头和基体材料的弹性特性。在两种温度下，弹性压痕均在 10 mN 的最大载荷下提供。室温和 150°C 下的加载-卸载曲线非常接近（在实验误差范围内），这证明了弹性性能在所考虑的温度范围内的稳定性。计算得出涂层的弹性模量为326 GPa。使用配备横向力传感器的同一装置，测定不同载荷（5、10 和 20 mN）下涂层的滑动摩擦系数。这样的研究可以被认为是涂层与单个粗糙体接触的物理模型。实验在 1 mm 长的直线轨道上以 11 µm/s 的速度进行。结果表明，涂​​层具有减摩性能（摩擦系数在 0.033—0.078 范围内）。摩擦系数随着负载的增加而增加，这可能是由于涂层材料在相对高负载下塑性变形的能量耗散所致。关于存在塑性变形的结论是基于光学轮廓测量的结果，该结果显示在相对高的载荷下沿着摩擦轨迹的边缘发生塑性变形并推动材料。在低负载时，不会观察到这种现象。该涂层可用于需要一次或两次低摩擦系数应用的滑动摩擦装置。