Microstructure and properties of a vacuum-tempered glass with low-temperature-sintered silver paste

A low-temperature sintered silver paste was used for the metallization of tempered glass, which was used to prepare vacuum-tempered glass by soldering with Sn96.5Ag3Cu0.5 paste (SAC305). The effects of the glass content and the sintering temperature on the microstructures, shear strengths, and fracture mechanisms of the bondlines were investigated in detail. The microstructure of the thick silver film and its interface with the tempered glass was characterized. The dissolution and precipitation behaviors of silver in Bi–B–Zn glass were also analyzed. Bi4B2O9 crystals were detected in the microstructure of the thick silver film when the joining temperature was increased above 450 °C, which can strengthen the silver film and the interface with the tempered glass. After soldering at 450 °C for 10 min, an excellent bondline was formed using the low-temperature sintered paste, which had a shear strength of 42.3 ± 2.4 MPa and a leak rate of 7.2 ± 0.4 × 10–3 Pa.cm3/s. The sintered paste had a composition of 80 wt.% silver and 20 wt.% glass powder. Furthermore, heat transfer tests revealed that the vacuum tempered glass had excellent thermal insulation properties. The results showed that the low-temperature sintered silver paste combined with soldering was an effective method to prepare vacuum-tempered glass.