Sealing process of Al₂O₃ ceramic with 7A52 aluminum alloy

7 A52 aluminum alloy and φ 10 mm nickel-plated alumina ceramic balls were encapsulated by brazing technology. Effects of heating temperature and holding time on microstructure characteristics,characteristic point composition and shear strength were studied. The results showed that optimum process parameters of 7 A52 aluminum alloy and Al₂ O₃（ Ni） ceramic sealing with silicon-magnesium solder were 590 ℃heating temperature,2 MPa pressure and 1 h holding time. Thickness of the reaction layer was 10 ～ 27 μm,and maximum shear strength of the joint reached 24. 8 MPa. The interface structure of the joint was Al₂O₃ ceramic/Al-Ni intermetallic compound/Al-Si eutectic/7 A52 aluminum alloy.