Silver assisted crack healing in SiC

Abstract

This paper provides a potential method through a dissolution-precipitation mechanism to achieve crack healing in SiC by a vacuum heat treatment with Ag at 1450 °C. The thermodynamic calculations and experimental results confirm that the Ag reacts with SiC to form a molten Ag-Si alloy and carbon, which accelerates material transport in SiC, and then by reaction between the Ag-Si and carbon, a new SiC is formed and fills inside the cracks and Vickers indentation impressions to achieve crack healing in SiC. The depth recovery ratio of the indentation is ∼60%. The cracks underneath the indentation break into a row of isolated nodules, which is driven by reducing the interfacial energy between SiC and the Ag-Si alloy.