FATIGUE LIFE LIMITATION OF CERAMIC MATERIALS DUE TO SURFACE CRACK PROPAGATION
Journal Title: Tribologia - Year 2009, Vol 224, Issue 2
Abstract
Some ceramic materials have been found to have the optimum combination of properties that are suitable for rolling element bearing applications (high speeds, high loads, different environments). Cracks, structure defects and manufacturing faults are the main problem connected with fatigue life. These defects decrease the rolling contact fatigue considerably. An experimental study of ring cracks propagation and structure defects propagation of zirconia and silicon nitride was also described in the paper. The rolling contact tests were performed on pre-cracked zirconia and silicon nitride upper balls using a modified (rolling lower balls) four-ball machine in specified lubricant. Ball surfaces and failures were examined using scanning electron microscopy. The paper contains the following: ⇒ The variation of test time for both ceramic materials balls with ring cracks defects was presented. ⇒ The mechanism of ring crack propagation in zirconia and silicon nitride was described. ⇒ The influence of pores on fatigue life of zirconia was described.<br/><br/>
Authors and Affiliations
Waldemar Karaszewski
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