Lowered sintering temperature and improved microwave dielectric properties in a vanadium tantalate via in-situ adjusting V5+/Ta5+ molar ratio

摘要

Compositional modification engineering was designed to simultaneously reduce the sintering temperature and improve the dielectric properties of BaTa2V2O11 via in-situ adjusting the V5+/Ta5+ molar ratio. A series of BaTa2-xV2+xO11 ceramics, fabricated by a solid-state reaction method, were characterized for structural evolution and dielectric properties variations. In-situ adjusting V5+/Ta5+ molar ratio significantly lowered the sintering temperature of BaTa2V2O11 and prominently improved the temperature stability of resonance frequency which is explained by the dielectric dilution theory. Competitive microwave dielectric properties with epsilon(r) = 11.5-25.9, Q x f = 22,172-42,660 GHz, and tau(f) = 42.4-74.6 ppm/oC were achieved in the BaTa2-xV2+xO11 ceramics sintered at 620-840 oC. All the results indicate that the molar ratio of V5+ is primarily responsible for improving the densification behavior and dielectric characteristics of BaTa2-xV2+xO11, which in turn increases the appropriateness in further practical applications.

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