Preparation of BaSm_2Ti_4O_(12) Microwave Dielectric Ceramics via a Polyacrylamide Precursor

摘要

A modified polyacrylamide precursor method is presented to synthesize BaSm_2Ti_4O_(12) microwave dielectric ceramics. Under an alkaline circumstance, all the cations together with the monomer and bridging agent were dispersed into a hydrous solution with the aid of chelating agent EDTA. This mixture was initiated at about 90℃, dried, calcined at 1000℃ for 2hs and finally turned into well-crystallized and single-phased BaSm_2Ti_4O_(12) ceramic powder, which was modeled and sintered at 1250℃ for 2hours into well-sintered ceramics. Differential thermal analysis, thermogravimetric analysis, X-ray powder diffraction and transmission electron microscope were used to characterize the process. Microwave dielectric properties measured by a resonating cavity method contain a dielectric constant (ε_r) about 77.0 and quality factor (Q×f) lager than 11000.