Reaction wetting behaviour of improved Ti-based brazing fillers on carbon/carbon composites at 1423–1573 K

Abstract

Ti-based brazing fillers for carbon/carbon composite (C/C) connections are very promising; however, there is a lack of research on this topic. The wetting behaviour and mechanism of Ti-Cu-Si fillers on C/C at 1423–1573 K were investigated in this study. When the temperature was less than 1473 K, the contact angle decreased with time because of TiC layer formation, which exhibited a large interfacial ideal adhesion work (Wad) of 9.815 J/m2. However, the contact angle increased abnormally over time when the temperature exceeded 1473 K. This nonwetting behaviour can be attributed to the formation of SiC and Ti3SiC2 phases, which naturally increased the interfacial energy and surface roughness and decreased Wad (Wad of TiCu/SiC was reduced to 3.669 J/m2), and this hinders the spread of the liquid on the C/C substrate. These results suggest that increasing the temperature does not necessarily imply an improvement in wettability, thereby providing a new idea for developing high-temperature solders for C/C welding.