Soldering Si3N4 to Invar42 by a localized heating process

This study investigates the soldering process for joining silicon nitride (Si3 N4 ),a commonly used ceramic, to Invar42, a low thermal expansion alloy. The focuslies on analyzing interfacial reactions and evaluating the bonding performance ofthe Si3 N4 —Invar42 joint. Field emission scanning electron microscopy (FESEM)and energy-dispersive X-ray spectroscopy (EDS) were employed to examine themicrostructure, elemental distribution, and chemical composition of the interfa-cial region. The results underscore the critical role of interfacial reaction layersin the soldering process. Mechanical testing (single lap offset, SLO, lap sheartests) was conducted to assess the bonding strength and mechanical integrity ofthe soldered joints. Furthermore, the thermal stability and reliability of thesejoints were evaluated through SLO tests at 300◦C. This study contributes tothe advancement of a user-friendly, pressureless, localized heating and field-deployable technique for soldering Si3 N4 to Invar42, thereby facilitating thefabrication of advanced engineering systems in industrial environments.