In this article, an attempt is made to explore the effects of normal force and temperature on the threshold displacement amplitudes of tin-plated electrical contacts at elevated temperatures. Fretting tests were conducted at 323, 348, and 373 K at normal forces of 1, 1.25, 1.5, and 2 N. Riders and flats made from a 0.3-mm-thick brass sheet were coated with $10~\mu \text{m}$ of tin. Dimples were commonly found at the center of the contact area of the test specimens corresponding to an unlimited lifetime. In the testing temperature range, the threshold displacement amplitude decreases with an increase in the temperature and with a decrease in the normal force. In this range, the threshold displacement amplitude was found to be controlled by the oxidation of a tin-plated surface. The activation energy was found to be 7.5 kJ/mole, which is close to the value of the activation energy for the growth of tin oxide film. The threshold displacement amplitude can be represented in the form of an Arrhenius equation and is proportional to the normal force.

中文翻译：

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高温微动条件下法向力对镀锡触点电耐久性的影响

本文尝试探索法向力和温度对温度升高时镀锡电触点的阈值位移幅度的影响。在323、348和373 K的法向力分别为1、1.25、1.5和2 N的情况下进行微动测试。由0.3毫米厚的黄铜板制成的车手和平台涂有 $ 10〜\ mu \ text {m} $ 锡。通常在试样接触区域的中心发现凹痕，对应于无限的使用寿命。在测试温度范围内，阈值位移幅度随温度的升高和法向力的降低而减小。在该范围内，发现阈值位移幅度由镀锡表面的氧化控制。发现活化能为7.5kJ /摩尔，这接近用于氧化锡膜生长的活化能的值。阈值位移幅度可以以Arrhenius方程的形式表示，并且与法向力成比例。