Ceramic-metal bonding is a key technique for the application of ceramics, especially , structural ceramics. Among the several bonding techniques which have been developed, the most available bonding technique is brazing.
In this study , bonding of $Al_2O_3$ were made with a 65wt.% Ag-33.5wt.% Cu-1.5Wt.% Ti alloy by vacuum brazing at 900℃ for 5 , 40min, and phases formed by reaction between the braze filler metal and the $Al_2O_3$ were analyzed for the phase identifications and their crystal structures. Two kinds of reaction layers with different growth rates were formed at the interface. In the early stage of reaction, the thin layer was composed of two kinds of titanium oxides : $Ti_2O$ and δ-TiO. and these layers changed into the δ-TiO with prolonged reaction time. The δ-TiO had a hexagonal structure with lattice parameters a=4.99$\dot{A}$ and c = 2.88$\dot{A}$. The thick layer was identified with the $Ti_4Cu_2O$ phase with a diamond cubic structure with a lattice parameter of a = 11.27$\dot{A}$. And then compositional variations were studied with the time variable(5, 40, 300, 1680min.). Regardless of the time, Ti exhaustion was observed in the filler metal right in front of reaction layers and on the interface of $Al_2O_3$ side, Al and O were existed as dissolved state. As reaction time increased, separation took place between the two reaction layers.