Lead magnesium niobate is a perovskite phase and has a high dielectric constant. However, it is difficult to produce since the pyrochlore phase always occurs in this material resulting infenor dielectric properties. In this research the magnesium niobate compound was synthesized by using corundum and columbite techniques. The suitable conditions of each technique such as a ratio of the starting materials, calcining temperature and soaking time were studied in the preparation. เท addition, the effect of lead magnesium niobate on the dielectric properties of bismuth sodium titanate was investigated in this thesis. The results of both techniques showed the mixed phases of MgNb2O6 Mg4Nb2O9 and Mg5Nb4O15. A ratio of MgO to Nb2O5 could not be used to obtain the pure phase of magnesium niobate as applied in corundum and columbite techniques since Mg(OH)2 was present in MgO. In this thesis the optimum condition to achieve a large amount of MgNb2O6 was 1200 °c firing temperature with a long soaking time. Higher than 1200 °c yielded an increasing amount of Mg4Nb2O9 and Mg5Nb4O15. In contrast, if firing at lower than 1200 °c, the starting matenals still remained with the mixed phases of magnesium niobate compound. The effect of lead magnesium niobate on the dielectric constant of bismuth sodium titanate was insignificant. Nevertheless, it decreased the cune temperature of bismuth sodium titanate as the amount of lead magnesium niobate increased.
