Microwave dielectric properties of Ba(Mg1/3Ta2/3)O-3 materials synthesizedby inverse-microemulsion process

Microwave dielectric properties of Ba(Mg1,3Ta2,3)O-3 (BMT) materials have b een improved by using an inverse-microemulsion process for preparing the BM T powders. The as-prepared powders, which are amorphous clusters about 100 nm in size, can be converted into pure perovskite phase BMT materials witho ut the formation of undesired secondary phase (BaTa4O15) by calcination pro cess. BMT materials with high enough density [95% theoretical density (TD)] of BMT samples can be obtained only by sintering the materials at 1600 deg reesC for 24 h. Low sinterability of thus prepared BMT powders is ascribed to the formation of aggregates in calcinations process. However, the sinter ed BMT samples exhibit very good microwave dielectric properties. The quali ty factor thus obtained, Q x f=65200 GHz, is markedly better than that of t he BMT materials prepared by conventional mixed oxide routes. The prime fac tor improving the microwave dielectric properties of the inverse-microemuls ion processed BMT materials is presumably the fine grain microstructure (1- 2 mum) of the samples. (C) 2001 Published by Elsevier Science Ltd. All righ ts reserved.