Joining alumina to metals: Technologies, challenges, and future prospects for high-performance structures

Technological advancements are expanding applications for alumina-to-metal components with higher performance demands, such as microelectronic packaging, wear-resistant components for aircraft, biomedical applications, and more. Manufacturing methods for reliable alumina-metal joints are reviewed. While diffusion bonding was initially significant, conventional brazing now leads in research and industrial use. Current efforts focus on developing active interlayers to improve alumina wetting and composite fillers to strengthen brazed joints. Diffusion bonding remains under study, but long joining times limit industrial adoption. Induction brazing, transient liquid phase bonding, and laser welding are emerging with enhanced efficiency, minimizing energy consumption, and a more sustainable process overall. Ultrasonic vibration-assisted brazing is also a promising joining technique, however, the joint temperature resistance is reduced. Future trends in the joining alumina-metal are directed to fast and flash joining techniques, hybrid joining processes, and the comprehension of the mechanisms underlying joint strength variations with differing processes under different joining conditions.