Effects of Starting Precursor on Phase and Microstructural Characteristics of Ferroelectric Lead Magnesium Niobate Ceramics
Suk anda Jiansirisomboon *, K amonpan P engpat and T awee T unk asiri* Author for corresponding; e-mail address: sukanda@chiangmai.ac.th
Volume: Vol.32 No.3 (SEPTEMBER 2005)
Research Article
DOI:
Received: -, Revised: -, Accepted: -, Published: -
Citation: Jiansirisomboon S.A.., Engpat K.A..P. and Asiri T.A..T.U., Effects of Starting Precursor on Phase and Microstructural Characteristics of Ferroelectric Lead Magnesium Niobate Ceramics, Chiang Mai Journal of Science, 2005; 32(3): 307-313.
Abstract
Ferroelectric lead magnesium niobate (Pb(Mg1/3Nb2/3)O3; PMN) ceramics were fabricated from different starting precursors using a columbite method. To receive high quality PMN powders, an optimization for high purity magnesium niobate (MgNb2O6; MN) powders was crucial. The MN powders were prepared using a mixed-oxide method from 2 groups of precursors. Group 1 (MN1) consisted of MgO and Nb2O5, while (MgCO3)4 Mg(OH)2.5H2O. was used instead of MgO in group 2 (MN2). It was found that calcination temperature of MN powder could be reduced by approximately 200°C when (MgCO3)4 Mg(OH)2.5H2O. was used instead of MgO as a base precursor. Both MN powders then reacted with PbO to form the PMN1 and PMN2 powders. At this stage, a pyrochlore second phase always formed with a main perovskite PMN phase. Microstructural investigation of the PMN ceramics showed well-dispersed large pyramidal pyrochlore grains among the PMN grains. Grain size of PMN1 ceramics were larger than those found in PMN2 ceramics.