Abstract
Interfacial reaction kinetics between Ag and ceramic-filled glass (CFG) substrate, containing borosilicate glass, high-silica glass, and alumina, has been investigated at 850°-925°C in different atmospheres. No chemical reaction at the interface of Ag/CFG is found when firing takes place in N 2 or N 2 + 1% H 2 . Fired in air, however, an interfacial reaction zone is formed at the interface of Ag/CFG with Ag + ion diffusing from silver and Al 3+ ion dissolving from CFG, and both ions are always coupled together in the reaction zone. Microstructural and chemical analyses show that the reaction zone consists of two distinct layers; one is homogeneous, and the other, heterogeneous. The homogeneous layer, which is adjacent to Ag, is uniform in microstructure with a composition rich in Ag + and Al 3+ . The heterogeneous layer is not uniform in microstructure with Si-rich and Ag-Al-rich phases. The reaction zone moves toward CFG with time, forming a heterogeneous layer first and then converting into a homogenous layer when diffusion of Ag + ion into the CFG becomes significant. The growth kinetics for the homogeneous layer follows a linear rate equation, whereas the heterogeneous layer, a parabolic rate equation. Activation analyses suggest that the formation of the homogeneous layer is controlled by the combination of breakage and formation of M-O bonds, but the heterogeneous layer, by the diffusion of Ag + ion in the BSG.