Wetting and reaction of BN-SiO_2 ceramic by molten Ti-40Ni-20Nb (at.%) filler alloy

摘要

The wetting behavior and the interfacial reactions of molten Ti-40Ni-20Nb (at.%) filler alloy on the BN-SiO2 ceramic were investigated by the a sessile drop method at 1453 K under a vacuum atmosphere. Results demonstrated that a good wettability with final contact angles of approximately 44 degrees-15 degrees was obtained. Interfacial microstructure examinations revealed that the Ti-40Ni-20Nb filler alloy reacted with the BN-SiO2 ceramic, which resulted in the formation of TiN, TiB, Ti5Si3 and Ti3O5 at the interface. The wetting process of the Ti-40Ni-20Nb filler alloy on the BN-SiO2 ceramic was identified into 3 stages: (i) rapid decreasing stage, (ii) sluggish spreading stage and (iii) final equilibrium stage. In order to reveal the essence of the reactive wetting, the wettability of the Ti-40Ni-20Nb (at.%) filler alloy on the BN-SiO2 ceramic with three different BN contents were investigated. For the Ti-40Ni-20Nb/BN-SiO2 system, the wettability mainly depended on the final interfacial chemistry of the system but the intensity of the interfacial reactions. The final contact angle of the Ti-40Ni-20Nb filler alloy on the BN-SiO2 ceramic decreased as the BN content in the ceramic was increased from 20% to 80%.