Joining of single-crystal sapphire to alumina using silicate glasses

Abstract

The joining of a sapphire single crystal plate to alumina ceramic tube is fabricated successfully using 34CaO·30Al2O3·36SiO2 glass as an interlayer. This glass showed good adhesion performance to alumina ceramics and sapphire single crystal. The joint with no crack was obtained by heating at 1550°C for 10 min and slow cooling from 1200°C to room temperature. From the thermal shock test, the half of the specimens showed the cracks after quenching from 225°C to 0°C, but all specimens showed no cracks after quenching from 200°C to 0°C. The specimen, composed of alumina tube-sapphire plate-alumina tube showed the comparable bending strength to the specimen composed of alumina tube-alumina tube.