Sintering Behavior and Surface Microstructure of PbO‐Rich PbNi_1/3Nb_2/3O₃–PbTiO₃–PbZrO₃ Ceramics

Abstract

The sintering behavior and surface microstructure of PbNi 1/3 -Nb 2/3 O 3 -PbTiO 3 -PbZrO 3 (PNiNb-PT-PZ) ceramics were investigated. The PNiNb-PT-PZ ceramics with the stoichiometric composition and the addition of excess lead oxide (PbO-rich ceramics) were sintered by liquid-phase sintering in accordance with the solution-reprecipitation mechanism at temperatures below the melting point of PbO. The temperature at which the liquid phase forms fell to near the eutectic point of the PbO-Nb 2 O 5 and the PbO-TiO 2 system (868°C) with the addition of 5 mol% PbO. As the calcination temperature influenced the sinterability of the stoichiometric PNiNb-PT-PZ ceramic, unreacted PbO was considered to be the source of the liquid phase in the sintering of the stoichiometric powder. The secondary phase was observed at the surface of PbO-rich ceramics and was suggested to be a liquid phase expelled from inside the ceramic. A sintering scheme of PNiNb-PT-PZ ceramics was proposed, and the high sinterability of PNiNb-PT-PZ ceramics was attributed to the low formation temperature of the liquid phase. Fig. 9. Scheme of the sintering behavior of the PbO-rich PNiNb-PT-PZ ceramics.

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