Articles
All articles | Recent articles
Effects of In-Situ-Formed 9Al2O3·2B2O3 on the Corrosion Resistance of Al2O3-Based Porous Ceramic in Molten Aluminum
R. Xiang, Y. Li, D. Xiang, N. Li, S. Li, S. Sang
The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, PR China
received July 23, 2015, received in revised form October 23, 2015, accepted November 11, 2015
Vol. 7, No. 1, Pages 113-118 DOI: 10.4416/JCST2015-00037
Abstract
White fused alumina (WFA), α-Al2O3 powder, aluminum hydroxide powder and pseudoboehmite powder (PB) are each mixed with boric acid according to the stoichiometric ratio of 9Al2O3·2B2O3 in order to study the formation process. For the corrosion experiment, Al2O3-based porous ceramic with and without the addition of boric acid is prepared and soaked in molten aluminum for 48 h at 870 °C. The results show that the synthesis temperature of 9Al2O3·2B2O3 is 1000 °C, except for the mixture of PB and boric acid for which the synthesis temperature is 900 °C. The corrosion resistance of the samples with the addition of boric acid in molten aluminum is improved because of the generation of 9Al2O3·2B2O3 around the pores.
Download Full Article (PDF)
Keywords
Porous ceramic, in-situ synthesization, 9Al2O3·2B2O3, molten aluminum, corrosion resistance
References
1 Larsen, D.A.: Degassing aluminum using static fine-pore refractory diffusers, JOM., 49, [8], 27 – 28, (1997).
2 Afshar, S., Allaire, C.: Furnaces: improving low cement castables by non-wetting additives, JOM., 53, [8], 24 – 27, (2001).
3 Obrien, M.H., Akinc, M.: Reduction in aluminum alloy attack on aluminosilicate refractories by addition of rare-earth oxides, J. Am. Ceram. Soc., 73, 491 – 495, (1990).
4 Aguilar-Santillan, J.: Wetting of Al2O3 by molten Aluminum: the influence of BaSO4 additions, J. Nanomater., 4, 145 – 152, (2008).
5 Adabifiroozjaei, E., Koshy, P., Sorrell, C.C.: Assessment of non-wetting materials for use in refractories for aluminium melting furnaces, J. Aust. Ceram. Soc., 51, 139 – 145, (2015).
6 Adabifiroozjaei, E., Koshy, P., Sorrell, C.C.: Effects of different boron compounds on the corrosion resistance of andalusite-based low-cement castables in contact with molten al alloy, Metall. Mater. Trans. B, 43, 5 – 13, (2012).
7 Wang, J., Ning, G., Lin, Y.: Chemical synthesis of Al18B4O33 whiskers via a combustion method, Mater. Lett., 62, 2447 – 2449, (2008).
8 Douy, A., Aluminium borates: synthesis via a precipitation process and study of their formation by DSC analysis, Solid State Sci., 7, 117 – 122, (2005).
9 Fischa, M., Armbruster, T., Rentsch, D., Libowitzky, E., Pettke, T.: Crystal-chemistry of mullite-type aluminoborates Al18B4O33 and Al5BO9: A stoichiometry puzzle, J. Solid State Chem., 184, 70 – 80, (2011).
10 Wang, J., Sha, J., Yang, Q., Wang, Y.W., Yang, D.R.: Synthesis of aluminium borate nanowires by sol-gel method, Mater. Res. Bull., 40, 1551 – 1557, (2005).
11 Levin, E.M., Robbins, C.R., McMurdie, H.F.: Phase diagrams for ceramicists, The American Ceramic Society, Inc., USA, 1987.
Copyright
Göller Verlag GmbH
