CaV2O6: A highly effective sintering aid for 0.61CaTiO3-0.39LaAlO3 ceramics

Abstract

The 0.61CaTiO3-0.39LaAlO3 (CTLA) ceramics are widely used in relay station, aerospace and radar systems for their superior properties: remarkable quality factor and excellent thermal stability. However, some deficiencies remain, such as low permittivity and excessively high sintering temperature, which limit their development in microwave communication. Herein, we introduce CaV2O6 to the CTLA ceramics to solve these problems and systematically investigate its effects on sintering temperature, phase constitution, microstructure and microwave dielectric properties. The CTLA ceramics added with 0–2.0 wt% CaV2O6 were prepared by the traditional solid-state reaction procedure. The XRD patterns indicated that the pure phase Ca0.61La0.39Al0.39Ti0.61O3 (PDF #52-1773) was obtained from all samples, which revealed that the CaV2O6 was dissolved into CTLA lattice to form a solid solution. As the CaV2O6 content increased, the strongest X-ray diffraction peaks gradually shifted toward low angles, which manifested the increase of cell volume of the solid solution. When the additive amount was 1.0 wt%, the CaV2O6 could high-effectively lower the sintering temperature from 1450 ℃ to 1290 ℃ and obviously promote the growth of grains. Meanwhile, the εr slightly increased, the Q×f significantly improved and the τf favorably decreased to closer to zero, then the prominent microwave dielectric performance was exhibited, with εr = 40.6, Q×f = 48,800 GHz (at 4.5 GHz), and τf = 0.78 ppm/℃. Such CTLA ceramics are expected to promote the development of high-performance and temperature-stable microwave components.