Improvement of Contact Strength in Ceramics by Crack-Healing

Abstract

Ceramics are expected as the structural materials but they are brittle materials. Therefore there is a possibility of rapid fracture when a contact stress intensively acts on the surface of materials. Therefore improvement of reliability is needed for ceramics used under a local contact stress. In response, the crack healing ability of ceramics is extremely effective. If the crack-healing ability of ceramics is used on structural components, great benefits can be anticipated, such as an increase in the reliability of structural ceramic members and a decrease in the inspection, machining and polishing costs of ceramic components. In the present study, the effects of the crack-healing on contact strength were investigated for Si_3N_4/SiC which was subjected to various machining process. The evaluation of contact strength was done by sphere indentation test that used acoustic emission (AE) together. As a result, the contact strength of Si_3N_4/SiC was improved by crack-healing with a combination of rapping even for the material that had machining cracks induced by a heavily machining process.