Understanding wetting mechanism of pure Cu on C/C composites modified by chromium carbide

Carbon fiber reinforced carbon matrix (C/C) composites are considered one of the key lightweight materials for high-temperature components. Unfortunately, C/C composites are difficult to be wetted by metals, seriously hindering their application in the engineering field. This study obtains a superior wettability of pure Cu on C/C composites modified by chromium carbide (Cr-C). Owing to Cr-C surface modification, the contact angle of pure Cu on C/C composites is significantly decreased from 159 degrees to 15 degrees. Notably, the spreading and wetting process in this study occurs once Cu melts, distinguished from the common reactive wetting. High Resolution Transmission Electron Microscope (HRTEM) examination demonstrates a direct interfacial joining between the Cr-C layer and Cu droplet without transition phases. Superior wettability can be attributed to the interfacial metallic bond of Cr-C and Cu phases. This work offers a promising surface modification strategy to enhance the wettability of carbon and ceramic substrates.