Enhanced Sintering Behaviour and Microwave Dielectric Properties of CaLa₄Ti₄O₁₅ Ceramics with ZnO–B₂O₃ Addition

Abstract—Effects of ZnO-B₂O₃ (ZB) addition have been investigated on the sintering behavior, structure and microwave dielectric properties of CaLa₄Ti₄O₁₅ ceramics. The sintering temperature of CaLa₄Ti₄O₁₅ ceramics with a very small amount of ZB addition such as 0.2 and 0.5% is obviously reduced from 1550 to 1375°C, and the sintering temperature range is significantly broadened to 1350–1450°C. With the increase of ZB addition, the secondary phases of CaLa₄Ti₅O₁₇ and LaBO₃ are observed in these ceramics. Not only sintering behavior but also microwave dielectric properties of CaLa₄Ti₄O₁₅ ceramics have been enhanced by a small amount of ZB addition. Excellent microwave dielectric properties of ε = 42.7, Qf = 46.678THz, τ_f = –3.5 ppm/°C are achieved for the CaLa₄Ti₄O₁₅ ceramics with 0.5% ZB addition sintered at 1375°C.