Effect of Debinding Conditions on the Microstructure of Sintered Pb(Mg1/3Nb2/3)O3-PbTiO3

In order to fabricate complex-shaped polycrystalline ceramics by sintering, organic binders are usually pre-mixed with ceramic powders to enhance the formability during the shape forming process. These organic binders, however, must be eliminated before sintering so as to eliminate the possibilities of poor densification and unusual grain growth during sintering. The present work studies the effect of binder addition on grain growth behavior during sintering of $92(70Pb(Mg_{1/3}Nb_{2/3})O_3-30PbTiO_3))$-8PbO(mol%) piezoelectric ceramics. The microstructures of the sintered samples were examined for various heating profiles and debinding schedules of the binder removal process. Addition of Polyvinyl butyral(PVB) binder promoted abnormal grain growth especially in incompletely debinded regions. Residual carbon appears to change the grain shape from comer-rounded to faceted and enhance abnormal grain growth.