Microstructure of high temperature Ti-based brazing alloys and wettability on SiC ceramic

Ti-based brazing alloys were prepared by the non-consumable arc-melting technology. The wettability behavior of the brazing alloys on silicon carbide (SiC) was investigated by means of sessile drop method in vacuum at 1400 °C for 10 min. The brazing alloys of 91.5Ti–8.5Si (wt.%), 87.1Ti–8.1Si–4.8Cu (wt.%) and 83.2Ti–7.7Si–9.1Cu (wt.%) exhibit good wettability on SiC plate, but bad cohesion with SiC after cooling. However, the brazing alloys of 22Ti–78Si (wt.%) and 21Ti–74.2Si–4.8Cu (wt.%) exhibit both good wettability and cohesion with SiC after cooling. Microstructure, phase composition of the brazing alloys and the interface between the brazing alloys and SiC were investigated by using SEM coupled with EDS and XRD, respectively.