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In this study, alumina ceramics with hierarchical pores were successfully fabricated using freeze casting. Experimental studies show that both the solid loading of the slurry and the thermal insulation layer at the interface of the slurry and cooling plate can influence the pore characteristics of cast samples. In order to examine the pore characteristics and evaluate the permeability of the freeze-cast samples fabricated under different conditions, a generative adversarial network (GAN) method was employed to reconstruct the three-dimensional (3D) microstructure from two-dimensional (2D) scanning electron microscopy (SEM) images of the samples. Furthermore, GAN 3D reconstruction was validated against X-ray tomography 3D reconstruction results. Based on the GAN reconstructed microstructures, the permeability and pore distribution of the various samples were analyzed. The sample cast with 35 wt.% solid loading shows an optimal permeability. [ABSTRACT FROM AUTHOR]

Research on polymer-based dielectric materials with low energy loss and high power density for dielectric capacitors can promote the development of advanced energy storage devices and effectively solve energy storage problems. In recent years, all-organic polymer dielectrics have received extensive attention due to the excellent properties and have shown broad development prospects in the energy storage industry. Compared to polymer inorganic composites with bad processability, all-organic dielectrics have proven to be a more suitable option for low-cost and large-scale production. This review summarizes the phased achievements of traditional all-organic polymer dielectrics and the recent progress in polymer modification technology. Meanwhile, the energy storage theory of dielectrics, such as energy storage parameters, polarization mechanisms, breakdown mechanisms, and conduction mechanisms, is thoroughly reviewed. Finally, this paper identifies the existing problems of all-organic polymer dielectric materials and proposes feasible solutions and possible future research priorities. [ABSTRACT FROM AUTHOR]

The behaviour of various powder systems during high temperature sintering has been investigated by coupling X-ray microtomography and discrete element method (DEM). Both methods are particularly relevant to analyse particle interactions and porosity changes occurring during sintering. Two examples are presented. The first one deals with a copper powder including artificially created pores which sintering has been observed in situ at the European synchrotron and simulated by DEM. 3D images with a resolution of 1.5 μm have been taken at various times of the sintering cycle. The comparison of the real displacement of particle centers with the displacement derived from the mean field assumption demonstrates significant particle rearrangement in some regions of the sample. Although DEM simulation showed less rearrangement, it has been able to accurately predict the densification kinetics. The second example concerns multilayer ceramic capacitors (MLCCs) composed of hundreds of alternated metal electrode and ceramic dielectric layers. The observation of Ni-based MLCCs by synchrotron nanotomography at Argon National Laboratory with a spatial resolution between 10 and 50 nm allowed understanding the origin of heterogeneities formed in Ni layers during sintering. DEM simulations confirmed this analysis and provided clues for reducing these defects.