Wettability and interfacial reactions of PdNi-based brazing fillers on
C-C composite
(Laboratory of Welding and Forging, Beijing Institute of Aeronautical Materials, Beijing 100095, China)
Abstract: The wettability and interfacial reactions of four kinds of PdNi-based brazing fillers on C-C composite were studied with the sessile drop method. The results showed that the wettability of these brazing fillers was improved with the increase of Cr content. Cr distributed at the interface of brazing filler/C-C composite and the formation of Cr23C6 phase was speculated. In the interface between Ni-33Cr-24Pd-4Si brazing filler and C-C composite, element Cr reacted with C-C to form Cr-C reaction layer. Pd together with Si participated in the interfacial reactions and formed Pd2Si and Pd3Si phases. Furthermore, in this reaction zone, the residual brazing alloy became Ni-rich and Pd-depleted.
Key words: PdNi-based brazing filler; diffusion layer; wettability; interfacial reaction