Ceramic oxide bonds using calcium aluminosilicate glasses

Glasses with compositions falling in the Ca-Al-Si-O system are used to bond oxide ceramics. Alumina, zirconia and an alumina-zirconia composite are used as ceramic components. Joints are obtained at temperatures slightly higher than the melting temperature of glass which, for the selected compositions, change from 1210 to 1410oC. The degree of interaction between the ceramic components and the glass interlayer is mainly influenced by the bonding temperature and by the cooling rate. Conversely, the presence of defects like pores at the ceramic-glass interfaces depends on the experimental technique adopted to deposit the glass onto the ceramic surface. The 3-point flexural strength of the joint is measured at room temperature and for selected samples at 500oC. The mechanical properties of the joints are related to the microstructure at the interface.