Microwave dielectric property modification of Ba4Nd9.33Ti18O54 ceramics by the substitution of (Al0.5Nb0.5)4+ for Ti4+ and the addition of NdAlO3

In this work, Ba4Nd9.33Ti18O54 (BNT) microwave dielectric ceramic materials fabricated by a conventional solid-state reaction method was compositionally modified via the replacement of Ti4+ by (Al0.5Nb0.5)(4+) and the addition of NdAlO3 to enhance the temperature stability (tau(f)) and quality factor (Qxf) of the BNT ceramic materials. In the ceramic samples of Ba4Nd9.33(Al0.5Nb0.5)(x)Ti18-xO54 (BNANT), an increase in the concentration of (Al0.5Nb0.5)(4+) (i.e., x from 0 to 1.6) effectively improved both the tau(f) (from 67.5 to 12.6 ppm/degrees C) and the Qxf (from 9260 to 10245 GHz) despite the fact that the excessively high concentration of (Al0.5Nb0.5)(4+) (i.e., x = 1.6) severely deteriorated the Qxf, and the tau f was ( )still not at a near-zero level. Therefore, NdAlO3 was introduced into the BNANT ceramic materials as a tau(f) compensator. In the binary system of (1-y)Ba4Nd9.33(Al0.5Nb0.5)(1.2)Ti16.8O54-yNdAlO(3), a near-zero tau(f) level of -2.06 ppm/degrees C with Qxf = 13680 GHz and dielectric constant (epsilon(r)) = 70 was achieved at y = 0.55.