Wetting and brazing of YIG ceramics using Ag–CuO–TiO 2 metal filler

摘要

The wetting and brazing of Y3Fe5O12(YIG) ceramics with a Ag–8CuO–2TiO2filler was investigated for the first time. For comparison, the wettability of a Ag–10CuO filler on YIG ceramics was similarly investigated. The Ag–8CuO–2TiO2filler has an equilibrium contact angle of approximately 31?°C on the YIG substrate at 1000?°C; thus, its wettability is excellent. Moreover, its wettability exceeds that of Ag–10CuO. The microstructure and the interfacial structure between the filler and the substrate were determined using scanning electron microscopy, X-ray diffraction, EPMA and transmission electron microscopy. The liquid Ag–8CuO–2TiO2filler can react with the YIG substrate by forming continuous Y2Ti2O7layers with dotted CuFe2O4and promote the wetting behavior and bonding performance. The average shear strength could exceed 30?MPa for the joints at a brazing temperature of 1000?°C. As rupture occurred adjacent to the seam at the ceramic side, the strengths of the interfaces were characterized via nanoindentation. The hardness of the interface with doped TiO2exceeds that of Ag–10CuO, which is strengthened by the dotted CuFe2O4among Y2Ti2O7.