An experimental investigation of rolling contact failure within silicon nitride subject to micro surface defects
Journal: 5th World Tribology Congress, WTC 2013
Due to low density, high stiffness, hardness and strength, and low coefficient of thermal expansion, silicon nitride ceramic is used in industry for rolling contact applications. Surface defects are the main limiting factor for the use of silicon nitride in hybrid ball bearings applications. These defects are of different nature and shape including cracks, surface pull-out also called missing material, or a combination of both. During this study, each ceramic rolling element is laser machined to simulate micro missing material within the surface subject to various contact pressures in lubricated rolling contacts. An experimental methodology is adopted using a modified four ball machine with micro surface defects positioned on the contact surface for rolling contact fatigue.