Slippery when dry – Eliminating friction on the nanoscale
Tutor / director / avaluadorvan Spengen, Merlijn
Tipus de documentProjecte/Treball Final de Carrera
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The present thesis is meant to be part of the research project ‘Slippery when dry – Eliminating friction on the nanoscale’ from TU Delft 3mE PME department, leadered by W. M. van Spengen and in cooperation with F. Buja. Concerning the research project as a whole, MEMS/NEMS (micro-/nano-electromechanical systems) are small, moving mechanical microstructures, like micromotors, accelerometers and chemical sensors. Although there have been scientific and commercial successes, reliability problems related to friction and wear prevent designers from taking full advantage of this technology. In this project, we will use a two-pronged approach towards solving friction and wear in MEMS: 1. the use of diamond-like carbon (DLC) coatings, and 2. films formed by vapour phase lubrication (VPL). Some DLC films macroscopically show almost vanishing friction (‘superlubricity’), which is not well understood. However, at the scale of MEMS, superlubric DLC has not been demonstrated. VPL involves carbon-containing molecules that condense between the contacting points of sliding surfaces and form a hard tribofilm. The basic physical principles are believed to be the same for the tribological behaviour of both DLC and VPL. It should be possible to induce superlubricity using VPL instead of DLC by tailoring the molecular composition of the vapour. This would be the best of both worlds, because VPL has the advantage over a DLC layer that it can be applied more easily in many complex MEMS devices. Since this research project requires making measurements with different devices in order to understand the friction on the nanoscale, the present thesis will focus on the resolution of such devices. Raman spectrometer and MEMS comb drive are examples of devices whose noise level can be studied, although the noise background theory is applicable to other kind of measurements.
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