Analysis of microsturcture evolution and mechanical properties in zirconia ceramic joints brazed by bismuth based glass

The ZrO 2 ceramics was successfully brazed by the newly designed bismuth-borate glass. The mechanism which is influenced by holding time and cooling rate on morphology and mechanical performance of joints were thoroughly analyzed under 675 °C. The study introduced an innovative bismuth-borate glass composition as the brazing material, providing an effective solution for high-strength joint formation in ZrO 2 ceramics. The findings showed that when brazing temperature was 675 °C, well-formed joints were obtained under 0–90 min and cooling rate range of air cooling or slower, whiskers of Al 4 B 2 O 9 and crystals of Al 5 BO 9 were observed in the joints, with their number and size increasing as the holding time extended and the cooling rate decreased. Systematic analysis demonstrated that the optimized process parameters, including a holding time of 30 min and a controlled cooling rate of 3 °C/min, resulted in a maximum shear strength of 83 MPa. The joint formed under these conditions was a reinforced composite consisting of aluminum borate crystals. The joint of ZrO 2 ceramics brazed with Bismuth oxide-Boron oxide-Aluminium oxide (50Bi 2 O 3 -45B 2 O 3 -5Al 2 O 3 ) glass is the reinforced composite joint consisting of aluminum borate crystals.