Low‐Temperature Firing and Microwave Dielectric Properties of Ca[(Li _1/3 Nb _2/3 ) _0.8 Ti _0.2 ]O _3−δ Ceramics with ZnB ₂ O ₄ Glass Addition

Low‐temperature sintered Ca[(Li _1/3 Nb _2/3 ) _0.8 Ti _0.2 ]O _3−δ microwave dielectric ceramics with ZnB ₂ O ₄ glass (ZBG) addition were prepared by the conventional solid state reaction method. The sintering behavior, microstructure, and microwave dielectric properties of Ca[(Li _1/3 Nb _2/3 ) _0.8 Ti _0.2 ]O _3−δ ceramics with ZBG addition were investigated. The ZBG addition lowered the densified temperature of Ca[(Li _1/3 Nb _2/3 ) _0.8 Ti _0.2 ]O _3−δ ceramics from 1150°C to 940°C. The dielectric constants of Ca[(Li _1/3 Nb _2/3 ) _0.8 Ti _0.2 ]O _3−δ ceramics decreased from 40 to 34 and the temperature coefficient of resonant frequency (τ _f ) changed gradually from +12.7 to −25.7 ppm/°C as ZBG addition increased from 0 to 8 wt%. The Q _f values increased greatly from 20,500 GHz of pure Ca[(Li _1/3 Nb _2/3 ) _0.8 Ti _0.2 ]O _3−δ to 26,900 GHz when 5 wt% ZBG was added. Ca[(Li _1/3 Nb _2/3 ) _0.8 Ti _0.2 ]O _3−δ ceramics with 8 wt% ZBG addition sintered at 940°C show good microwave dielectric properties with ɛ _r ∼32.5, Q _f ∼20,600 GHz, and τ _f ∼−25.7 ppm/°C. The relationship between dielectric properties and microstructure was also discussed.