Citation
Polkowski, Wojciech and Sobczak, Natalia and Nowak, Rafal and Kudyba, Artur and Bruzda, Grzegorz and Polkowska, Adelajda and Homa, Marta and Turalska, Patrycja and Tangstad, Merete and Safarian, Jafar and Moosavi-Khoonsari, Elmira and Datas Medina, Alejandro
(2017).
Wetting behavior and reactivity of molten silicon with h-BN substrate at ultrahigh temperatures up to 1750 °C.
"Journal of Materials Engineering And Performance"
(n. 27);
pp. 1-14.
ISSN 1059-9495.
https://doi.org/10.1007/s11665-017-3114-8.
Abstract
For a successful implementation of newly proposed silicon-based latent heat thermal energy storage systems, proper ceramic materials that could withstand a contact heating with molten silicon at temperatures much higher than its melting point need to be developed. In this regard, a non-wetting behavior and low reactivity are the main criteria determining the applicability of ceramic as a potential crucible material for long-term ultrahigh temperature contact with molten silicon. In this work, the wetting of hexagonal boron nitride (h-BN) by molten silicon was examined for the first time at temperatures up to 1750 °C. For this purpose, the sessile drop technique combined with contact heating procedure under static argon was used. The reactivity in Si/h-BN system under proposed conditions was evaluated by SEM/EDS examinations of the solidified couple. It was demonstrated that increase in temperature improves wetting, and consequently, non-wetting-to-wetting transition takes place at around 1650 °C. The contact angle of 90° ± 5° is maintained at temperatures up to 1750 °C. The results of structural characterization supported by a thermodynamic modeling indicate that the wetting behavior of the Si/h-BN couple during heating to and cooling from ultrahigh temperature of 1750 °C is mainly controlled by the substrate dissolution/reprecipitation mechanism.