In situ characterization of advanced ceramic sintering processes

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In situ characterization of advanced ceramic sintering processes

The past decade has seen the development of several novel methods that allow ceramics to be densified at thermal budgets considerably lower than used in traditional sintering, which typically requires temperatures above 1000 °C.  One prominent example is ceramic cold sintering [1] that, under only moderate uniaxial pressure, can yield nearly theoretical density at temperatures ranging from slightly above ambient to a few hundred degrees Celsius. In addition to significantly reducing a carbon footprint, this technology permits the co-sintering of ceramics with metals and polymers, opening new opportunities for processing devices and components.   Another novel method is ultrafast high-temperature sintering [2].  In this approach, the temperatures are as high as in conventional processes, but the exposure is shortened from hours to seconds.  Such ultrafast heating rates, combined with their specific implementation method, allow for the sintering of complex shapes enabled by ceramic additive manufacturing and prevent unwanted reactions and diffusion in multi-material parts.  Successful industrialization of these new sintering technologies requires a thorough understanding of their underlying physical mechanisms, which is still incomplete.

This NRC opportunity complements the ongoing efforts within the Materials Measurement Science Division of NIST to exploit advanced in situ characterization methods, such as synchrotron-based X-ray scattering or spectroscopic probes, for characterizing the evolution of materials during sintering [3].   Some potential research directions could include developing sample stages that enable novel ceramic processing (like cold sintering) while allowing for real-time measurements of structural, chemical, microstructural, and phase changes in the material.  Another direction is to develop and perform such measurements to gain a comprehensive understanding of the fundamental mechanisms that govern the novel sintering methods.

1. J. Guo, R. Floyd, S. Lowum, J.-P. Maria, T. Herisson De Beauvoir, J.-H. Seo, C.A. Randall, Cold Sintering: Progress, Challenges, and Future Opportunities, Ann. Rev. Mater. Res. 49, 275-295 (2019). https://doi.org/10.1146/annurev-matsci-070218-010041 .

2.     C. Wang, W. Ping, Q. Bai, H. Cui, R. Hensleigh, R. Wang, A.H. Brozena, Z. Xu, J. Dai, Y. Pei, C. Zheng, G. Pastel, J. Gao, X. Wang, H. Wang, J.C. Zhao, B. Yang, X. Zheng, J. Luo, Y. Mo, B. Dunn, L. Hu, A general method to synthesize and sinter bulk ceramics in seconds, Science 368 (2020) 521–526. https://doi.org/10.1126/science.aaz7681 .

3. F. Zhang, R. A. Maier, I. Levin, A.J. Allen, J. S. Park, P. Kenesei, I. Kuzmenko, In situ probing of interfacial roughness and transient phases during ceramic cold sintering process. Acta Mater. 259, 119283 (2023) https://doi.org/10.1016/j.actamat.2023.119283

advanced ceramic processing, ceramic sintering; in situ characterization; X-ray scattering

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