Enhancement of the bonding strength of Al2O3 ceramics using a reactive intermediate layer formed by aerosol deposition

Bonding with glass frit is important in many applications. Glass frit should wet and react chemically with the substrate. Its glass-wetting properties were improved by applying a lead oxide (PbO) layer fabricated through aerosol deposition (AD) which reacted with the glass frit. The 13 mu m-thick PbO AD layer, which was mechanically anchored to the substrate, disappeared during bonding, since the PbO layer became diffused into the glass. The glass pellets on the PbO layer reacted with each other and were spread out at 455 degrees C, which is lower than the equivalent temperature for glass frit on alumina (470 degrees C) without an AD layer because of changes in the glass structure, as confirmed by Fourier-transform infrared (FT-IR) spectroscopy. The coefficient of thermal expansion (CTE) hardly changed. These phenomena increased the bonding strength at the glass-substrate interface of each specimen from 133.61 kPa (without AD) to 180.21 kPa (with AD).