Wear mechanisms in microfabricated ball bearing systems

Microfabricated ball bearings have been demonstrated successfully in a number of microsystems, although a complete understanding of their tribological properties remains elusive. This paper investigates the wear mechanisms for a microfabricated ball bearing platform that includes silicon and thin-film coated silicon raceway/steel ball materials systems. Adhesion of ball material, found to be the primary wear mechanism, is universally present in all tested materials systems. Volumetric adhesive wear rates are observed between 4 10 4 and 4 10 5 mm/mN rev. Pressured-induced phase changes take place in the contact areas of the bare silicon raceways, observed with Raman spectroscopy. An understanding of the wear mechanisms within microfabricated ball bearings will help optimize operational parameters and materials systems for long-term reliability. & 2015 Elsevier B.V. All rights reserved.