Influence of Zn addition on wettability of AgCu brazing alloy on TiC cermet

Wetting experiments of AgCu eutectic brazing alloy and AgCuZn brazing alloy with 30wt.% Zn addition were performed on TiC cermet. Based on observation of wetting angles of the two brazing alloys on the cermet and interfacial microstructure, it is found that wettability of brazing alloy on TiC cermet is greatly improved by Zn addition. When AgCu brazing alloy was adopted, the microstructure was Ag(s.s)+Cu(s.s)/(Cu, Ni)+Ag(s.s)/TiC cermet+Ag(s.s)+Cu(s.s)/TiC cermet from the near exterior surface of the alloy to the cermet. However, when Zn was added into AgCu brazing alloy, the microstructure was Ag(s.s)+Cu(s.s)+(Cu, Ni)/Ag(s.s)+Cu(s.s)/(Cu, Ni)/TiC cermet+Ag(s.s)+ Cu(s.s)/TiC cermet. And it's shown that evaporation of Zn in the vacuum improves dissolution and diffusion of Ni at the interface and the wetting angle of the brazing alloy on the cermet decreases from 120.6° to 33.9°.