Numerical simulation and experimental verification of dry pressed MgTiO3 ceramic body during pressureless sintering

To clarify the densification law of dry pressed MgTiO₃ ceramic body during pressureless sintering, SOVS model (Skorohod-Olevsky Viscous Sintering model) modified with creep characteristics was embedded into finite element software Abaqus. The selected model can effectively express the grain boundary characteristics and densification mechanism. The change law of relative density, shrinkage rate, sintering stress, and grain size of MgTiO₃ cylindrical specimens was investigated by the above numerical simulation method. It showed that the average relative density of ceramic body rose from 60% to 97%, and the shrinkage rate respectively reached 17.28% and 11.99% in axial and radial direction. The average grain size increased from 1 to 6 μm. In order to verify the accuracy of the simulation results, corresponding sintering experiments on cylindrical specimens were carried out to obtain actual sintering densities and shrinkage rates. It showed that the errors of relative density and shrinkage were below 5% and 2%. Grain growth trend was also basically consistent with the simulation results. After that, the above numerical simulation method was applied into the prediction of fabricating MgTiO₃ filter with complex structure. Therefore, the present work provided a reliable numerical simulation method to predict the densification behavior of MgTiO₃ ceramics during the pressureless sintering process, which was helpful to design and fabricate microwave dielectric products.