Facile Synthesis of “Quench-Free Glass” and Ceramic-Glass Composite for LTCC Applications

Abstract

The 10 mol% ZnO–2 mol% B2O3–8 mol% P2O5–80 mol% TeO2 (ZBPT) glass was prepared by quenching as well as slowly cooling the melt. The ZBPT glass prepared by both methods show similar microwave dielectric properties. ZBPT glass has an εr of 22.5 (at 7 GHz), Qu × f of 1500 GHz, and τf of −100 ppm/°C. The ceramic-glass composites of Sr2ZnTeO6 (SZT) and ZBPT is prepared through two convenient methods: (a) conventional way of co-firing the ceramic with ZBPT glass powder and (b) a nonconventional facile route by co-firing the ceramic with precursor oxide mixture of ZBPT glass at 950°C. In the former route, SZT + 5 wt% ZBPT composite sintered at 950°C showed moderately good microwave dielectric properties (εr = 13.4, Qu × f = 4500 GHz and τf = −52 ppm/°C). Although the SZT + 5 wt% ZBPT composite prepared through the nonconventional method also showed similar microwave dielectric properties (εr = 13.8, Qu × f = 5300 GHz and τf = −50 ppm/°C), the synthesis procedure is much simplified in the latter case. The composites are found to be chemically compatible with Ag. The composite containing 5 wt% ZBPT prepared through conventional and nonconventional ways shows linear coefficients of thermal expansion of 7.0 ppm/°C and 7.1 ppm/°C, respectively. Both the composites have a room-temperature thermal conductivity of 2.1 Wm−1 K−1