Ahn Taemin, Song Sungmin, Ham Ungdon, Kim Tae-Hwan
Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, South Korea.
Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, South Korea.
Rev Sci Instrum. 2023 Jun 1;94(6). doi: 10.1063/5.0147344.
Piezoelectric motors are widely used in various applications where both precision positioning and miniaturization are required. Inertial or quasi-static motors are commonly employed because of their high accuracy, which demands consistent sliding friction between moving sliders and their static counterparts for reliable operation. In general, slider wear is unavoidable after long-term use. This wear can often lead to more serious cold welding in vacuum, which is also referred to as friction welding induced by direct contact between similar metal surfaces. Non-metallic coatings can prevent such unwanted cold welding in ultrahigh vacuum (UHV) applications. However, the practical reliability of available coatings under UHV conditions still remains to be elucidated. Here, we systematically investigate the practical reliability of commonly used, UHV-compatible lubricant coatings for piezoelectric motors in vacuum. We demonstrate that polytetrafluoroethylene (PTFE) shows the most reliable long-term operation in vacuum, while other coatings eventually lead to wear-induced cold welding and motor failure. Our findings provide a simple and effective method to improve the long-term performance of UHV piezoelectric motors by coating the slider surface with PTFE.
压电电机广泛应用于各种需要精密定位和小型化的场合。惯性或准静态电机因其高精度而被普遍采用，这种高精度要求运动滑块与其静止对应物之间具有一致的滑动摩擦力才能可靠运行。一般来说，滑块在长期使用后磨损是不可避免的。这种磨损常常会在真空中导致更严重的冷焊，冷焊也被称为由相似金属表面直接接触引起的摩擦焊。非金属涂层可以防止在超高真空（UHV）应用中出现这种不必要的冷焊。然而，现有涂层在超高真空条件下的实际可靠性仍有待阐明。在此，我们系统地研究了用于真空压电电机的常用超高真空兼容润滑涂层的实际可靠性。我们证明，聚四氟乙烯（PTFE）在真空中表现出最可靠的长期运行，而其他涂层最终会导致磨损引发的冷焊和电机故障。我们的研究结果提供了一种简单有效的方法，通过用聚四氟乙烯涂覆滑块表面来提高超高真空压电电机的长期性能。
