Reactive wetting of TiC-Ni cermet by Ag-Cu-Zn alloy during evaporation

In order to investigate the effect of the evaporation on wetting, reactive wetting of TiC-Ni cermet by molten Ag-Cu-Zn alloys with different Zn contents was studied at 810 degrees C using a sessile drop method in vacuum. The vapor recoil force induced by the strong evaporation of Zn in the Ag-Cu-25Zn alloy drove the spreading of the molten Ag-Cu-25Zn alloy. Furthermore, the sequential evaporation of Zn in the AgCu-25Zn alloy caused the formation of a (Cu, Ni) solid-solution layer at the interface between the TiC-Ni cermet and the Ag-Cu-Zn alloy. Thus, the (Cu, Ni) solid-solution layer could serve as a metallization layer on the surface of the TiC-Ni cermet, which promoted the non-wetting to wetting transition of the TiC-Ni cermet by the Ag-Cu-25Zn alloy. The equilibrium contact angle of the Ag-Cu-25Zn alloy on the TiC-Ni cermet was 19.9, approximately equal to that of a Ag-28Cu eutectic alloy on a Cu-Ni alloy surface. The final contact angle of the Ag-Cu-Zn liquid alloy on the TiC-Ni cermet first decreased and then increased as the Zn content in the liquid was increased from 0% to 30%. It reached a minimum value in the Ag-Cu-25Zn alloy. (C) 2017 Elsevier Ltd. All rights reserved.