Low temperature liquid phase sintering of lead magnesium niobate

It has been observed that PbO (21-5 wt%) is a good sintering aid for low temperature rapid sintering (950 degrees C, 30 min) of lead magnesium niobate (PMN) provided the PMN powder is coarse (average particle size similar to 16 mu m or more). For finer PMN powders, along with the same excess of PbO, (1-2 wt%) excess MgO is needed to achieve the same densification. The excess MgO (along with excess PbO) has been found to increase the fluidity of the liquid phase at the sintering temperature leading to liquid penetration inside the finer capillaries of the finer PMN powder with consequent rearrangement and densification. The peak dielectric constant (similar to 12 000) of MgO added sample was found to be lower than that of the samples containing no excess MgO (K similar to 13500) because of the presence of impurity pyrochlore phase in the MgO added samples. (C) 1999 Elsevier Science Limited and Techna S.r.l. All rights reserved.