Development of MgAl₂O₄ spinel coating on graphite surface to improve its water-wettability and oxidation resistance

Titelangaben

Saberi, Ali ; Golestani-Fard, Farhad ; Sarpoolaky, Hosein ; Willert-Porada, Monika ; Gerdes, Thorsten ; Simon, Reinhard ; Liebscher, Christian H.:
Development of MgAl₂O₄ spinel coating on graphite surface to improve its water-wettability and oxidation resistance.
In: Ceramics International. Bd. 35 (2009) Heft 1 . - S. 457-461.
ISSN 1873-3956
DOI: https://doi.org/10.1016/j.ceramint.2007.12.007

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Abstract

Low water-wettability and oxidation resistance of graphite have limited its application in carbon containing refractory castables. The aims of this study are the improvement of water-wettability and the oxidation resistance of natural flaky graphite by applying an oxide coating on its surface. To develop the coating, magnesium aluminate spinel sol was formulated via a citrate--nitrate route and graphite powder was then added to the sol. The mixture was heat treated in appropriate temperature and atmosphere to get the polycrystalline MgAl2O4 coating on graphite particles surface. The microstructure of coating was studied by X-ray diffractometer, SEM and TEM. The water-wettability was evaluated by measuring the water drop contact angle and plotting the zeta potential vs. pH. The results showed the development of a stable nanocrystalline MgAl2O4 spinel coating which improved the water-wettability and oxidation resistance of graphite significantly. Also, characterization of the coating is explained with emphasis on its application importance.