Synthesis and characterization of lead silicate glass

Synthesis of lead silicate glass suitable for fabrication of compression ty pe glass-to-metal seals has been studied. A three- stage heating schedule w as evolved for the preparation of glass. While some of the constituents wer e taken in the form of oxides, the others were either carbonates or nitrate s. Differential thermal analysis revealed that the glass prepared by follow ing nitrate mute had a higher softening point. This analysis also brought o ut the presence of an endothermic transformation around 465 degrees C in al l the samples. Electron spectroscopy for chemical analysis suggested that t his transformation was due to the presence of some carbonate. The glass pow der synthesized was found to be suitable for making seals which could withs tand pressures up to 1.2 x 10(4) psi and vacuum of the order of 10(-8) Ton.