BaO-TiO2 microwave ceramics

In this paper, the structure and dielectric properties of BaO-TiO2 system ceramics were studied. By adding ZnO and Nb2O5 as sintering agents to the raw materials, the BaO-TiO2 system ceramics were sintered at a temperature of 1260 degreesC for 2 h and have superior dielectric properties at 1 GHz: quality factor Q = 12,500, relative dielectric constant epsilon(r) approximate to 37, temperature coefficient of dielectric constant alpha(epsilon) = 0 +/- 30 ppm/degreesC. XRD pattern shows that the main crystal phase of the ceramics is Ba2Ti9O20, accompanied by a small number of additional phases: BaTi4O9, Ba4Ti13Zn7O34, Ba4Ti13O30 and Ti2Nb10O29, etc. The initial Ba/Ti ratio has a great effect on the dielectric properties of the ceramics, which can be explained by the variance in the formation of phases due to different Ba/Ti ratios. (C) 2003 Published by Elsevier Ltd.