Effect of glass fluxing on densification and microwave dielectric properties of LiInSiO4 ceramic

Abstract

A novel microwave substrate ceramic LiInSiO4 (LIS) was synthesized by solid-state ceramic route. LIS ceramic sintered at 1150 degrees C for 4 h showed a densification of 91% with epsilon(r) = 8.2, Q(u) x f = 12,600 GHz and tau(f) = -55 ppm/degrees C. Its thermal conductivity at room temperature (T-c) was found to be 6.0 Wm(-1) K-1 and coefficient of thermal expansion (CTE) was 6.0 ppm/degrees C. For improving the relative density and dielectric properties of LIS ceramic, B2O3 and Lithium Magnesium Zinc Borosilicate (LMZBS) glasses were added. LIS + 1 wt.% LMZBS glass sintered at 1100 degrees C for 4 h showed a relatively good densification of 95% with moderate dielectric properties (epsilon(r) = 8.4, Q(u) x f = 22,000 GHz, tau(f) = -45 ppm/degrees C).