Wetting of Silicon Carbide by Cu-Si Alloys

Abstract

Knowledge of the characteristic features of the Cu/SiC interface is of basic concern in relation to the properties of SiC-Cu alloy composite materials. Wettability in the Cu/SiC system is a major variable for obtaining composites by the liquid infiltration process. The contact angle between pure Cu and SiC at 1100 °C is 140° and the bonding is weak, furthermore investigations of the wetting properties of molten Cu with SiC have shown that Cu decomposes SiC to form a Cu-Si alloy and graphite. Addition of small amount of Si to the copper has also been observed to inhibit the Cu-SiC reaction. The variation with temperature and time of the contact angle formed by molten Cu-Si alloys with two types of polycrystalline SiC (with and without free Si) was measured by the sessile drop method in a vacuum between 10 A to 10 -5 Pa at 1200°C. The obtained specimens were subsequently characterized by Scanning Electron Microscopy and EDX in order to study the interaction between the aforementioned metallic systems and SiC, and the type of interface developed after such treatment.