Synthesis of BaCu(B ₂ O ₅ ) Ceramics and their Effect on the Sintering Temperature and Microwave Dielectric Properties of Ba(Zn _1/3 Nb _2/3 )O ₃ Ceramics

Abstract

BaCu(B 2 O 5 ) ceramics were synthesized and their microwave dielectric properties were investigated. BaCu(B 2 O 5 ) phase was formed at 700°C and melted above 850°C. The BaCu(B 2 O 5 ) ceramic sintered at 810°C had a dielectric constant (ɛ r ) of 7.4, a quality factor ( Q × f ) of 50 000 GHz and a temperature coefficient of resonance frequency (τ f ) of −32 ppm/°C. As the BaCu(B 2 O 5 ) ceramic had a low melting temperature and good microwave dielectric properties, it can be used as a low‐temperature sintering aid for microwave dielectric materials for low temperature co‐fired ceramic application. When BaCu(B 2 O 5 ) was added to the Ba(Zn 1/3 Nb 2/3 )O 3 (BZN) ceramic, BZN ceramics were well sintered even at 850°C. BaCu(B 2 O 5 ) existed as a liquid phase during the sintering and assisted the densification of the BZN ceramic. Good microwave dielectric properties of Q × f =16 000 GHz, ɛ r =35, and τ f =22.1 ppm/°C were obtained for the BZN+6.0 mol% BaCu(B 2 O 5 ) ceramic sintered at 875°C for 2 h.