Speaker
Description
Thermal energy storage systems using metallic alloys require chemically compatible containment. Where the container sits between the storage material and a heat exchanger, good thermal contact is also important. In order to select such a container, processes at the liquid-solid interface between the metallic phase change material and the housing material have to be understood. Low reactivity and good wetting behaviour are the most relevant aspects in comparing material suitability.
Compatibility and wetting behaviour between the eutectic metallic phase change material Al Si12.5wt% and potential ceramic and metallic housing materials were investigated. The study was performed using several techniques. A custom-built furnace was utilised to observe the reaction behaviour after high-temperature holds of varying lengths. The wetting behaviour was analysed using a Sessile Drop Apparatus. Both apparatuses were developed and built in-house at the Institute of Materials Physics in Space at the German Aerospace Centre in Cologne, Germany.
The subsequent microstructure analysis reveals the formation of striking reaction product layers and inclusions at the interface between Al Si12.5wt% and those candidate housing materials that were found compatible after the experiments in the custom-built furnace. The reaction phases are identified using EDX and EBSD analysis providing evidence towards the suitability of housing materials. Contact angles were measured after Sessile Drop experiments and, where reactive wetting was observed, the temporal behaviour recorded.
Comparison of the compatibility behaviour observed in experiments performed in the custom-built furnace and during the Sessile Drop experiments will be presented. Moreover, an appraisal of which housing material selected for this study is the most suitable, is provided – at least from a chemical compatibility and wetting behaviour point of view.
| Speaker Country | Germany |
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