Effect of Bi ₂ O ₃ Doping on the Sintering Temperature and Microwave Dielectric Properties of Li Al SiO ₄ Ceramics

Abstract

When Bi 2 O 3 was added to Li Al SiO 4 ceramics, Bi 12 SiO 20 secondary phase was formed. Since the melting temperature of Bi 12 SiO 20 ceramics is 880°C, the liquid phase is expected to form during sintering and to assist the densification of Li Al SiO 4 ceramics. When 15.0 mol% Bi 2 O 3 was added, the Li Al SiO 4 ceramics could be sintered at 900°C, and with 20.0 mol% Bi 2 O 3 they could even be sintered at 875°C. The 15.0 mol% Bi 2 O 3 ‐doped Li Al SiO 4 ceramics sintered at 900°C exhibited good microwave dielectric properties, namely, a low ε r of 4.3, a high Q × f of 62 430 GHz and a small τ f of −16.21 ppm/ o C.