Achieving excellent wetting of inactive Ag on C/C composites by a low-temperature surface modification strategy

Carbon fiber reinforced carbon matrix (C/C) composites are one of the most promising thermal lightweight materials. However, the inferior wettability of inactive metals on C/C composites severely limits their application for joining alloys in industrial structures. In this study, successful wetting of inactive Ag on C/C composites is achieved via a low-temperature surface modification strategy. After surface modification using a chromium carbide (CrC) layer, the contact angle of Ag droplets on C/C substrates decreases significantly from 158° to 26°. Results of microstructure analysis indicate that no new reaction phases are generated during the wetting process. The wetting and spreading process of Ag droplets on CrC modified C/C substrates are promoted by the diffusion from Ag to CrC layer, which is found for the first time in this study. This study provides a novel surface modification concept for the wetting of C/C composites and other carbon materials.