High Temperature Stability of Nitride Ceramic Materials in LiF-NdF3-Nd2O3 Molten Salts System

LiF-NdF3-Nd2O3 용융염에서 질화물계 세라믹재료의 고온안정성

Kwon, Sukcheol;Lee, Young-Jun;Ryu, Hong-Youl;Lee, Go Gi;Jo, Sung Koo;Lee, Jong-Hyeon

  • Received : 2015.09.22
  • Accepted : 2015.10.27
  • Published : 2015.12.27


Nd-Fe-B permanent magnets have been used in a wide variety of applications because of their high magnetic flux density. So, demand for neodymium has been increasing in worldwide. In this study, an electrowinning process was performed in $LiF-NdF_3-Nd_2O_3$ high temperature molten salts. However, a corrosion resistant material for use in the molten salt must be found for stable operation because of the harsh corrosion environment of the electrowinning process. Therefore, for this paper, boron nitride(BN), aluminum nitride(AlN), and silicon nitride($Si_3N_4$) were selected as protective and structural materials in the high temperature electrolyte. To investigate the characteristics of BN, AlN, and $Si_3N_4$, in molten salts, materials were immersed in the molten salts for 24, 72, 120, and 192 hours. Also, surface condition and stability were investigated by SEM and EDS and corrosion products were calculated by HSC chemistry. As a result, among BN, AlN, and $Si_3N_4$, AlN was found to show the best protective material properties.


nitride ceramic materials;neodymium;electrowinning;protective material


  1. G. J. Kipouros and R. A. Sharma, J. Electrochem. Soc., 137, 3333 (1990).
  2. E. Stefanidaki, C. Hasiotis and C. Kontoyannis, Electrochim. Acta, 46, 2665 (2001).
  3. H. Y. Ryu, J. H. Lee, W. G. Kim, H. H. Nersisyan, G. G. Lee, S. K. Jo, H. H. Lee and I. S. Hwang, Rare Met., 34, 111 (2015).
  4. S. H. Cho, S. S. Hong, D. S. Kang, M. S. Jeong, B. H. Park, J. M. Hur and H. S. Lee, J. Korean Radioact. Waste Soc., 8, 33 (2010).
  5. M. A. Uusitalo, P. M. J. Vuoristo and T. A.Mantyla, Corros. Sci., 46, 1311, (2004).
  6. R. A. Rapp, Corros. Sci., 44, 209 (2002).
  7. J. G. Gonzalez-Rodriguez, S. Haro, A. Martinez-Villafane, V. M. Salinas-Bravo and J. Porcayo-Calderon, Mater. Sci. Eng. A, 435-436, 258 (2006).
  8. M. Spiegel, P. Biedenkopf and H. J. Grabke, Corros. Sci., 39, 1193 (1997).
  9. B. Zhu and G. Lindbergh, Electrochim. Acta, 46, 2593 (2001).
  10. B. P. Mohanty and D. A. Shores, Corros. Sci., 46, 2893 (2004).
  11. A. Ruh and M. Spiegel, Corros. Sci., 48, 679 (2006).
  12. J. E. Indacochea, J. L. Smith, K. R. Litko, E. J. Karell and A. G. Raraz, Oxid. Met., 55, 1 (2001).
  13. J. Eichler and C. Lesniak, J. Eur. Ceram. Soc., 28, 1105 (2008).
  14. Hugh O. Pierson, Handbook of refractory carbides and nitrides ; properties, characteristics, processing, and applications, Noyes publications, pp. 238-241 (1996).
  15. W. S. So and K. H. Baik, Korean J. Mater. Res., 21, 106 (2011).
  16. A. Roine, HSC Chemistry 6.1, Outotkumpu Research Oy, Pori, Finland (2006).
  17. S. H. Cho, J. H. Lim, J. H. Chung, J. M. Hur, C. S. Seo and S. W. Park, J. Korean Ind. Eng. Chem., 15, 913 (2004).
  18. J. A. Dean, Lange's handbook of chemistry, p. 329-341, McGRAW-HILL, INC., New York, (1999).
  19. V. L. Cherginets, V. N. Baumer, S. S. Galkin, L. V. Glushkova, T. P. Rebrova and Z. V. Shtitelman, Inorg. Chem., 45, 7367 (2006).
  20. X. Li, L. Zhang and X. Yin, Ceram. Int., 39, 3035 (2013).
  21. Y. P. Zaikov, A. A. Redkin, A. A. Apisarov, I. V. Korzun, N. P. Kulik, A. V. Isakov, A. A. Kataev and O. V. Chemezov, J. Chem. Eng. Data, 58, 932 (2013).


Supported by : Korea Institute of Energy Technology Evaluation and Planning(KETEP)