Porous materials, such as metal-organic frameworks emerge to solve important quests of our modern society, such as CO2 sequestration. Zeolitic Imidazolate Frameworks (ZIFs) can undergo a glass transition to form ZIF-glasses; they combine the liquid handling of classical glasses with tremendous potential for gas separations. Using millimeter-sized ZIF-62 single crystals and centimeter-sized ZIF-62-glass we demonstrate scalability and processability. Further, following the evolution of gas penetration into ZIF-crystals and ZIF-glasses by IR microimaging techniques enables to determine diffusion constants and changes to the pore architecture on the Angstrom-scale. The evolution of ZIF-glasses is observed in situ using a microscope heating stage. The pore-collapse during glass-processing is tracked by changes to density and volume of the glasses. Mass spectrometry investigates the crystal-to-glass transition and thermal processing ability.

No abstract

No abstract

Recently, microwave sintering has absorbed remarkable attention on the basis of enhanced microstructural/mechanical characteristics in comparison with conventional sintering techniques based on powder technology. This method not only can be employed for the processing of metals, alloys, and metal matrix composites but also for the manufacturing of advanced ceramics and ceramic matrix composites. Zirconium diboride (ZrB2) as an interesting member of ultrahigh temperature ceramics is one of the most undertaking candidates in modern structural ceramics applications. This paper reviews the processing-densification-mechanical properties correlations in microwave-sintered ZrB2-based ceramics and composites. The text concentrates on the microwave-assisted production of ZrB2 divided into two categories: synthesis of ZrB2 powders by microwave sintering and sintering of ZrB2-based ceramics and composites by microwave sintering. The effects of some additives and reinforcements, such as B4C, SiC, TiC, and MgO, on zirconium diboride's densification and mechanical properties are summarized.