Study on Rheological Behavior and Mechanical Properties of PMN–PZT Ceramic Feedstock

In this research, rheological behavior and mechanical properties of lead magnesium niobate–lead zirconate titanate (PMN–PZT) ceramic feedstock have been studied. Rheological behavior and mechanical properties of feedstock are the critical factors to manufacture a micro-scale piezoelectric structure with high aspect ratio because they highly affect the complete-filling as well as demolding process. Each feedstock was divided into three groups based on the variation of binder composition within the filler, backbone, and entire binder system. The optimal solids loading was determined based on the measurement of the critical solids loading, and 2 vol% lower solids loading than the critical state was adopted with all the feedstocks. Rheological specification of the feedstock was evaluated by means of twin-bore capillary rheometer test under various shear rates and temperatures. Using rheological analysis, key parameters including viscosity, flow behavior index, and flow activation energy were acquired. General moldability index as a function of the key rheological parameters was calculated and analyzed, and the feedstock with the lowest solids loading exhibited the best rheological character. In the next step, the mechanical properties of green parts were evaluated by the triple-point flexure test. The flexural stress and elastic modulus were significantly affected by the solids loading rather than binder composition. In general, this paper explored both rheological behavior and mechanical properties of PMN–PZT feedstock for various binder systems and it provides valuable guidance for the manufacture of a high-end micro-sized piezoelectric structure with high aspect ratio.