Optimization of sintering behavior and microwave dielectric properties of LaNbO4 ceramics with NiO/CoO additive

Abstract

LaNbO4 ceramics with NiO/CoO addition were designedly prepared through the conventional solid-state reaction. Compared with the pure LaNbO4 ceramics, attractively lower sintering temperatures and better microwave dielectric properties had been reached in the additive samples. The sintering behavior of the additive ceramics were characterized by the densities. For phase composition of LaNbO4-NiO/CoO ceramics, two phases were indexed as monoclinic fergusonite structure of LaNbO4 and isometric structure of NiO/CoO separately. The dielectric constants of LaNbO4-NiO/CoO ceramics had been analyzed by densities and polarizability. The quality factors (Q×f values) could be distinctly optimized to 95,050 GHz by NiO addition and 62,100 GHz by CoO addition, respectively. Moreover, intrinsic and extrinsic factors on the Q×f values had been further discussed relying on Raman spectrum and grain size analysis, with grain size (which refer to the extrinsic factors) being consequently verified to play the dominant role.