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Highly porous yttrium oxide is fabricated as ion beam target material in order to produce radioactive ion beams via the Isotope Separation On Line (ISOL) method. Freeze casting allows the formation of an aligned pore structure in these target materials to improve the isotope release. Aqueous suspensions containing a solid loading of 10, 15, and 20 vol% were solidified with a unidirectional freeze-casting setup. The pore size and pore structure of the yttrium oxide freeze-casts are highly affected by the amount of solid loading. The porosity ranges from 72 to 84% and the crosslinking between the aligned channels increases with increasing solid loading. Thermal aging of the final target materials shows that an operation temperature of 1400 °C for 96 h has no significant effect on the microstructure. Thermo-mechanical calculation results, based on a FLUKA simulation, are compared to measured compressive strength and forecast the mechanical integrity of the target materials during operation. Even though they were developed for the particular purpose of the production of short-lived radioactive isotopes, the yttria freeze-cast scaffolds can serve multiple other purposes, such as catalyst support frameworks or high-temperature fume filters.

Herein, hot‐spot generation in bulk barium titanate samples is investigated during controlled current ramping at various rates using in situ dilatometry. The incubation of the flash event is separated from dielectric breakdown at high current densities, which has previously been attributed to cause flash incubation in barium titanate. The lower boundary of the onset temperature of the flash event in barium titanate is investigated through conventional flash experiments at high electric fields. Despite incubating through thermal runaway, the lower boundary does not coincide with the Debye temperature of barium titanate.

Corrosion is one of the most common wear mechanisms of refractories. Corrosive attacks lead to chemical and microstructural changes. Hot corrosion compromises chemical and/or physical interactions. Thus, the process is complex and not yet fully understood. Currently, corrosion is investigated post mortem by means of X-ray diffraction or scanning electron microscopy. These methods have the drawback that some information is lost on cooling. In-situ measurements, however, take measurements within the process. In resonant frequency and damping analysis (RFDA), a sample is excited to vibrate by a mechanical impulse. The vibrating sample emits an acoustic signal. This is recorded with a microphone and evaluated by means of Fast Fourier Transformation (FFT). We measured the change of the frequency of a low cement castable during the corrosion process. Further simplified experiments with less complex materials were done to confirm the results. Distinctive points of the curves could be correlated to specific corrosion phenomena, like melting or infiltration. The applied methods include a first characterization of the material with open porosity, density and in-situ high-temperature (HT)-RFDA measurements as well as a study of the slag behavior.

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