Glasses and glass-ceramics
United States Patent 3935019
Rapp January 27, 1976
Glasses Patent Abstract
Thermally crystallizable glasses are disclosed of the system: wherein RO is a BaO or SrO. Also disclosed are thermally crystallizable glasses of the system PbO — Nb.sub.2 O.sub.5 — GeO.sub.2. Glass-ceramics made from these glass systems have high dielectric constants and low dissipation factors or loss tangents, which glasses and glass-ceramics are suitable for use as capacitors and dielectrics, and particularly for thick-film dielectric pastes utilized in the manufacture of micro-electronic printed circuits. By varying the heat treatment schedule for crystallization of the glass to a glass-ceramic, a specific high dielectric constant coming within a prescribed range can be imparted to the finished glass-ceramic.