Challenges for Lubrication in High Speed MEMS

Breuer, Kenneth; Ehrich, F. F.; Fréchette, Luc; Jacobson, S. A.; Lin, Chuang-Chia; Orr, D. J.; Piekos, Edward S.; Savoulides, N.; Wong, Cynthia F.

doi:10.1007/978-1-4615-1023-9_17

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…Consequently, cantilever acceleration sensors used as automotive airbag actuators are designed as limited range threshold detectors, rather than wide range measuring devices. Rotating devices such as pinwheels [3] and microturbines [5] have been fabricated, but are frequently subject to stiction problems that prevent start-up [1], or wear-related failure after a few minutes of operation [2]. In order to be able to realize the full potential of MEMS, it will be necessary to produce MEMS devices that survive under conditions of significant rolling and sliding contact under extreme environmental conditions.…”

Section: Si As a Mems Materialsmentioning

confidence: 99%

Materials science and fabrication processes for a new MEMS technology based on ultrananocrystalline diamond thin films

Auciello¹,

Birrell²,

Carlisle³

et al. 2004

J. Phys.: Condens. Matter

180

104

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Most MEMS devices are currently based on silicon because of the available surface machining technology. However, Si has poor mechanical and tribological properties which makes it difficult to produce high performance Si based MEMS devices that could work reliably, particularly in harsh environments; diamond, as a superhard material with high mechanical strength, exceptional chemical inertness, outstanding thermal stability and superior tribological performance, could be an ideal material for MEMS. A key challenge for diamond MEMS is the integration of diamond films with other materials. Conventional CVD thin film deposition methods produce diamond films with large grains, high internal stress, poor intergranular adhesion and very rough surfaces, and are consequently ill-suited for MEMS applications. Diamond-like films offer an alternative, but are deposited using physical vapour deposition methods unsuitable for conformal deposition on high aspect ratio features, and generally they do not exhibit the outstanding mechanical properties of diamond. We describe a new ultrananocrystalline diamond (UNCD) film technology based on a microwave plasma technique using argon plasma chemistries that produce UNCD films with morphological and mechanical properties that are ideally suited for producing reliable MEMS devices. We have developed lithographic techniques for the fabrication of UNCD MEMS components, including cantilevers and multilevel devices, acting as precursors to microbearings and gears, making UNCD a promising material for the development of high performance MEMS devices. We also review the mechanical, tribological, electronic transport, chemical and biocompatibility properties of UNCD, which make this an ideal material for reliable, long endurance MEMS device use.

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Section: Si As a Mems Materialsmentioning

confidence: 99%

Materials science and fabrication processes for a new MEMS technology based on ultrananocrystalline diamond thin films

Auciello¹,

Birrell²,

Carlisle³

et al. 2004

J. Phys.: Condens. Matter

180

104

View full text Add to dashboard Cite

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“…Other methods stabilize the rotor by eliminating or at least diminishing the cross-coupled terms with respect to the direct terms [31,37].…”

Section: Stabilization Methodsmentioning

confidence: 99%

“…This increases the eccentricity resulting in smaller cross-coupling terms in comparison to the direct terms. MIT tried to implement this method in their microturbine [31]. They aimed at eccentricity levels in the order of 0.9 and higher.…”

Section: Stabilization Methodsmentioning

confidence: 99%

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Micropower generation with microgasturbines: A challenge

Peirs

Waumans

Vleugels

et al. 2007

Proceedings of the Institution of Mechanical Engineers, Part C:

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This paper describes the development of a microgasturbine with a rotor diameter of 20 mm. The target electrical power output lies around 1 kW. The total system fits in a cylinder with a diameter of 95 mm and a length of 120 mm. The system contains the same components as a large gasturbine generator: compressor, recuperator, combustion chamber, turbine, and electrical generator. Major challenges are the high rotational speed (500 000 r/min), high turbine inlet temperature (1200 K), and the efficiency of the components. Because of the small dimensions, the flow through compressor and turbine is characterized by relatively low Reynolds numbers. The higher flow losses and inherently lower efficiency require a higher blade tip speed (524 m/s) than for large turbines (300-400 m/s). To minimize wear and frictional losses, the rotor is mounted on aerodynamic bearings. To withstand the high centrifugal stresses, a high-strength steel is used for compressor and shaft. The turbine is made of a Si3N4-TiN ceramic composite to withstand the combination of elevated stress and temperature.

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