Microstructure and mechanical properties of tempered glass joint bonded with Bi-B-Zn low melting glass

Abstract Soda lime tempered glass was successfully joined by a Bi-B-Zn lead-free low-melting glass with a composition of 35Bi2O3-50H3BO3-15ZnO (mol%). The Bi-B-Zn glass exhibited a glass transition temperature (Tg), softening point (Td) and crystallization temperature (Tc) of 346 ℃, 364 ℃and 448 ℃ respectively. The wettability of the glass on tempered glass substrate was investigated, and a contact angle of less than 13.94° was obtained when the temperature was raised to above 470 ℃ in open atmosphere. The microstructural evolution, interfacial bonding mechanism and mechanical properties of the joint at different joining temperatures were investigated. The diffusion bonding between Bi-B-Zn glass solder and tempered glass was achieved. The crystals of Bi4B2O9 were detected in the joint when the joining temperature was higher than 450 ℃. The shear strength and Vickers hardness of the joint reached 35.14 ± 1.89 MPa and 191.55 ± 13.93 MPa, respectively. The effects of the fractions and size of Bi4B2O9 on the shear strength were evaluated, and the fracture mechanism at the interface was also clarified.