Low loss Ba3Ti4Nb4O21 microwave dielectric ceramics through (Mn1/3Nb2/3)4+ ion control engineering for LTCC applications

In this work, a new low loss Ba3Ti4-x(Mn1/3Nb2/3)(x)Nb4O21(MN-BTN, 0 <= x <= 12 mol%) ceramics configuration was presented through preparing by the solid-state route. The XRD patterns, Rietveld refinement, microstructure, and microwave properties were systematically analyzed. All the fabricated MN-BTN ceramics belonged to the hexagonal structure with a P6(3)/mcm space group. More specifically, the 6MN-BTN ceramic exhibited a high relative density of similar to 92.3 %, homogeneous grains distribution with an average size of similar to 71.95 mu m, and several excellent microwave dielectric properties: epsilon(r) = 59.67, Qxf= 16,226 GHz, tau(f) = +103.9 ppm/degrees C sintered at 1220 degrees C. The incorporation of 1.5 wt% BaCu(B2O5) (BCB) compound within the 6MN-BTN ceramic not only effectively reduced the sintering temperature from 1220 degrees C to 950 degrees C, but also the excellent microwave dielectric properties were maintained: epsilon(r) = 42.33, Qxf = 11,300 GHz, tau(f) = +24.7 ppm/degrees C. Interestingly, the 6MN-BTN + 1.5 wt% BCB ceramic showed better chemical compatibility with Ag. The proposed 6MN-BTN + 1.5 wt% BCB ceramic configuration could be regarded as a promising material for LTCC applications. (C) 2022 Elsevier B.V. All rights reserved.