Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Molten salt shielded synthesis of oxidation prone materials in air

Abstract

To prevent spontaneous oxidation during the high-temperature synthesis of non-oxide ceramics, an inert atmosphere is conventionally required1,2. This, however, results in high energy demand and high production costs. Here, we present a process for the synthesis and consolidation of oxidation-prone materials, the ‘molten salt shielded synthesis/sintering’ process (MS3), which uses molten salts as a reaction medium and also to protect the ceramic powders from oxidation during high-temperature processing in air. Synthesis temperatures are also reduced, and the final product is a highly pure, fine and loose powder that does not require additional milling steps. MS3 has been used for the synthesis of different ternary transition metal compounds (MAX phases, such as Ti3SiC23, Ti2AlN4, MoAlB5), binary carbides (TiC) and for the sintering of titanium. The availability of high-quality powders, combined with energy and cost savings, may remove one of the bottlenecks for the industrial application of these materials.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: MS3 process and the synthesized/sintered materials.
Fig. 2: Thermal analysis of KBr-encapsulated Ti3SiC2 and Ti.
Fig. 3: Interaction of Ti and Ti3SiC2 with molten salt.
Fig. 4: Temperature–purity regime for different phases synthesized by conventional routes.

Similar content being viewed by others

Data availability

The authors confirm that all the data generated and necessary to interpret the scientific findings are available within the paper. Extra data can be obtained from the corresponding authors upon request.

References

  1. German, R. Sintering: From Empirical Observations to Scientific Principles (Elsevier, 2014).

  2. Rahaman, M. Sintering of Ceramics (CRC, 2007).

  3. Barsoum, M. W. & El-Raghy, T. Synthesis and characterization of a remarkable ceramic: Ti3SiC2. J. Am. Ceram. Soc. 79, 1953–1956 (1996).

    Article  CAS  Google Scholar 

  4. Barsoum, M. W., El-Raghy, T. & Ali, M. Processing and characterization of Ti2AlC, Ti2AlN, and Ti2AlC0.5N0.5. Metall. Mater. Trans. A 31, 1857–1865 (2000).

    Article  Google Scholar 

  5. Kota, S. et al. Synthesis and characterization of an alumina forming nanolaminated boride: MoAlB. Sci. Rep. 6, 26475 (2016).

    Article  CAS  Google Scholar 

  6. Barsoum, M. W. MAX Phases: Properties of Machinable Ternary Carbides and Nitrides (Wiley, 2013).

  7. Boyer, R. R. An overview on the use of titanium in the aerospace industry. Mater. Sci. Eng. A 213, 103–114 (1996).

    Article  Google Scholar 

  8. Singh, R., Lee, P. D., Dashwood, R. J. & Lindley, T. C. Titanium foams for biomedical applications: a review. Mater. Technol. 25, 127–136 (2010).

    Article  CAS  Google Scholar 

  9. Qian, M., Schaffer, G. B. & Bettles, C. J. in Sintering of Advanced Materials 324–355 (Elsevier, 2010).

  10. Froes, F. H., Eylon, D., Eichelman, G. E. & Burte, H. M. Developments in titanium powder metallurgy. JOM 32, 47–54 (1980).

    Article  CAS  Google Scholar 

  11. Dunand, D. C. Processing of titanium foams. Adv. Eng. Mater. 6, 369–376 (2004).

    Article  CAS  Google Scholar 

  12. Ryan, G. E., Pandit, A. S. & Apatsidis, D. P. Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique. Biomaterials 29, 3625–3635 (2008).

    Article  CAS  Google Scholar 

  13. Xue, W., Krishna, B. V., Bandyopadhyay, A. & Bose, S. Processing and biocompatibility evaluation of laser processed porous titanium. Acta Biomater. 3, 1007–1018 (2007).

    Article  CAS  Google Scholar 

  14. Davis, N. G., Teisen, J., Schuh, C. & Dunand, D. C. Solid-state foaming of titanium by superplastic expansion of argon-filled pores. J. Mater. Res. 16, 1508–1519 (2001).

    Article  CAS  Google Scholar 

  15. Torres, Y., Pavón, J. J. & Rodríguez, J. A. Processing and characterization of porous titanium for implants by using NaCl as space holder. J. Mater. Process. Technol. 212, 1061–1069 (2012).

    Article  CAS  Google Scholar 

  16. Oh, I.-H., Nomura, N., Masahashi, N. & Hanada, S. Mechanical properties of porous titanium compacts prepared by powder sintering. Scr. Mater. 49, 1197–1202 (2003).

    Article  CAS  Google Scholar 

  17. Kimura, T. Advances in Ceramics—Synthesis and Characterization, Processing and Specific Applications (InTech, 2011).

  18. Gogotsi, Y. Materials Science of Carbides, Nitrides and Borides (Springer, 1999).

  19. Parker, E. R., Pask, J. A., Washburn, J., Gorum, A. E. & Luhman, W. Ductile ceramics—a high temperature possibility. JOM 10, 351–353 (1958).

    Article  CAS  Google Scholar 

  20. Gorum, A. E., Parker, E. R. & Pask, J. A. Effect of surface conditions on room temperature ductility of ionic crystals. J. Am. Ceram. Soc. 41, 161–164 (1958).

    Article  CAS  Google Scholar 

  21. Yoon, K. H., Cho, Y. S. & Kang, D. H. Molten salt synthesis of lead-based relaxors. J. Mater. Sci. 33, 2977–2984 (1998).

    Article  CAS  Google Scholar 

  22. Wang, Q. et al. The equilibrium between titanium ions and titanium metal in NaCl-KCl equimolar molten salt. Metall. Mater. Trans. B 44, 906–913 (2013).

    Article  CAS  Google Scholar 

  23. Selloni, A., Carnevali, P., Car, R. & Parrinello, M. Localization, hopping, and diffusion of electrons in molten salts. Phys. Rev. Lett. 59, 823–826 (1987).

    Article  CAS  Google Scholar 

  24. Liu, X., Fechler, N. & Antonietti, M. Salt melt synthesis of ceramics, semiconductors and carbon nanostructures. Chem. Soc. Rev. 42, 8237–8265 (2013).

    Article  CAS  Google Scholar 

  25. Hu, C., Sakka, Y., Tanaka, H., Nishimura, T. & Grasso, S. Fabrication of textured Nb4AlC3 ceramic by slip casting in a strong magnetic field and spark plasma sintering. J. Am. Ceram. Soc. 94, 410–415 (2011).

    Article  CAS  Google Scholar 

  26. Murugaiah, A. et al. Tape casting, pressureless sintering, and grain growth in Ti3 SiC2 compacts. J. Am. Ceram. Soc. 87, 550–556 (2004).

    Article  CAS  Google Scholar 

  27. Gonzalez-Julian, J., Classen, L., Bram, M., Vaßen, R. & Guillon, O. Near net shaping of monolithic and composite MAX phases by injection molding. J. Am. Ceram. Soc. 99, 3210–3213 (2016).

    Article  CAS  Google Scholar 

  28. Nan, B., Yin, X., Zhang, L. & Cheng, L. Three-dimensional printing of Ti3SiC2-based ceramics. J. Am. Ceram. Soc. 94, 969–972 (2011).

    Article  CAS  Google Scholar 

  29. Tian, W. B., Wang, P. L., Kan, Y. M. & Zhang, G. J. Cr2AlC powders prepared by molten salt method. J. Alloys Compd 461, L5–L10 (2008).

    Article  CAS  Google Scholar 

  30. Guo, X., Wang, J., Yang, S., Gao, L. & Qian, B. Preparation of Ti3SiC2 powders by the molten salt method. Mater. Lett. 111, 211–213 (2013).

    Article  CAS  Google Scholar 

  31. Tzenov, N. V. & Barsoum, M. W. Synthesis and characterization of Ti3AlC2. J. Am. Ceram. Soc. 83, 825–832 (2004).

    Article  Google Scholar 

  32. Gao, N. F., Li, J. T., Zhang, D. & Miyamoto, Y. Rapid synthesis of dense Ti3SiC2 by spark plasma sintering. J. Eur. Ceram. Soc. 22, 2365–2370 (2002).

    Article  CAS  Google Scholar 

  33. Zhang, Z. F., Sun, Z. M. & Hashimoto, H. Rapid synthesis of ternary carbide Ti3SiC2 through pulse-discharge sintering technique from Ti/Si/TiC powders. Metall. Mater. Trans. A 33, 3321–3328 (2002).

    Article  Google Scholar 

  34. Zhou, Y. & Sun, Z. Temperature fluctuation/hot pressing synthesis of Ti3SiC2. J. Mater. Sci. 35, 4343–4346 (2000).

    Article  CAS  Google Scholar 

  35. Pinho, S. & Macedo, E. Experimental measurement and modelling of KBr solubility in water, methanol, ethanol, and its binary mixed solvents at different temperatures. J. Chem. Thermodyn. 34, 337–360 (2002).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was funded by Germany’s Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung) under the MAXCOM project (03SF0534).

Author information

Authors and Affiliations

Authors

Contributions

A.D. proposed the original idea and carried out the experiments. J.G.-J. supervised A.D. All authors contributed to discussion of the results and writing of the manuscript.

Corresponding author

Correspondence to Apurv Dash.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figures 1–4, Supplementary Tables 1–3, Supplementary References 1–34

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Dash, A., Vaßen, R., Guillon, O. et al. Molten salt shielded synthesis of oxidation prone materials in air. Nat. Mater. 18, 465–470 (2019). https://doi.org/10.1038/s41563-019-0328-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41563-019-0328-1

This article is cited by

Search

Quick links

Nature Briefing: Translational Research

Sign up for the Nature Briefing: Translational Research newsletter — top stories in biotechnology, drug discovery and pharma.

Get what matters in translational research, free to your inbox weekly. Sign up for Nature Briefing: Translational Research