Solid state and solution synthesis of Ba(Mg1/3Ta2/3)O-3: A comparative study

Abstract

Ba(Mg1/3Ta2/3)O-3 [BMT] dielectric ceramics are prepared by solid state (one step, two step and molten salt synthesis) and wet chemical methods (precipitation, citrate gel and sol-gel). The formation mechanism of BMT in each synthesis technique is discussed. The formation temperature and particle size of the formed BMT were found to be much lesser (in nanometer range) for solution synthesized powders. It is found that synthesis by sol-gel method resulted in the formation of ultra pure nanopowders of BMT at about 600 degrees C with average crystallite size of about 18 mn where as in solid state synthesis the formation of BMT was formed at about 1100 degrees C with average crystallite size of 220 run. On sintering these powders, densification and grain growth of the chemically derived powders were found to be lower than that of solid state synthesized BMT powder. This has resulted in a slight decrease in density and microwave dielectric properties of the solution synthesized BMT samples. It is found that the microwave dielectric properties improved with increase in the average grain diameter of the sintered BMT ceramics