The Effect of Technological Factors on the Synthesis of PbMg 1/3 Nb 2/3 O 3

Conventional technique of solid phase reactions allows one to obtain PbMg 1/3 Nb 2/3 O 3 material with about 20 vol.% of the pyrochlore phase. The latter can be reduced to 5 vol.% by Swartz-Shrout two-stage solid state reaction via MgNb 2 O 6 having the columbite structure. A single-phase perovskite product can be obtained by by the two-stage columbite method from mixtures containing 0.2 mol. parts of overstoichiometric MgO. The best results are obtained by using magnesium carbonate hydroxide pentahydrate (MgCO 3 ) 4 ·Mg(OH) 2 ·5H 2 O as the magnesium source. The modified route yields stoichiometric single-phase PMN.