SiO2-CaO-Al2O3 glass solder for joining of Al2O3 for Al2O3

To utilize glass as a solder for joining of ceramics, the joining of Al2O3 to Al2O3 by glass solders with the compositions (mass %) of 33SiO(2)-34CaO-33Al(2)O(3) and 50SiO(2)-38CaO-12Al(2)O(3) has been investigated. The thermal expansion of these glasses and the wettability between glasses and alumina have been measured to confirm the applicability of the glasses to joining of alumina. After joining at various temperatures, the bending strength of the joint was measured using a four-point-bending test at room temperature. The joint interface between alumina and glass solders was observed using a SEM-EDX microanalyser. A maximum bending strength of 210 MPa was obtained for a joint produced at 1773 K for 1.2 ks with 33 SiO2-34CaO-33Al(2)O(3) solder. This value corresponds to 70% of that for original, alumina.