Please click Additional Files below to see the full abstrac

Ferreira, Paulo

Ribeiro, Camila

Senos, Ana

Vilarinho, Paula M.

Zorro, Fátima

English

Engineering Conferences International

UNDERSTANDING FLASH SINTERING OF SEMICONDUCTOR OXIDE MATERIALS AT THE NANO-ATOMIC SCALE  Fátima Zorro, International Iberian Nanotechnology Laboratory, Instituto Superior Técnico – IDMEC fatima.zorro@tecnico.ulisboa.pt  Camila Ribeiro, CICECO – Aveiro Institute of Materials, University of Aveiro  Ana Senos, CICECO – Aveiro Institute of Materials, University of Aveiro  Paula M. Vilarinho, CICECO – Aveiro Institute of Materials, University of Aveiro Paulo Ferreira, International Iberian Nanotechnology Laboratory, Instituto Superior Técnico – IDMEC, Materials Science and Engineering Program - University of Texas at Austin  Key Words: Flash Sintering, Semiconductor Oxide Materials, TEM, in-situ TEM. As the demand for energy-efficient technologies increases, it is critical to develop processes that produce materials at a lower cost. In this context, flash sintering (FS) is a viable alternative to conventional sintering, leading to a reduction of the processing times from hours to seconds, and a decrease in operating temperatures. Recently, room temperature FS was reported in the literature for materials such as ZnO or YSZ, however, the relationship between the micro/nanoscale properties and the physical mechanisms operating during FS is not fully understood [1], [2]. Also, the investigation of these mechanisms on semiconductor oxides is scarce. This is important as this class of materials has a wide range of applications due to their properties such as superconductivity, ferroelectricity, and dielectric assets [3]. Previous work demonstrates that the electrical response of piezoelectric ceramics is related to the defect formation and kinetics during the flash event [4], [5].  In this work, ex-situ FS studies of dense La0.75Sr0.25CrO3 bulk samples were performed at room temperatures. FS processing parameters were correlated to the nano/atomic structure, such as average grain size, grain size distribution, and composition distribution, obtained through TEM/STEM coupled with EDS. An investigation of the electrochemical reduction of species after FS, likely due to thermal runaway and defect migration, was conducted with aberration-corrected TEM/STEM coupled with Mono EELS. In this way, both the valence state of chromium and the distribution of oxygen were mapped before and after FS. Additionally, the grain boundaries were characterized by aberration corrected TEM/STEM to identify the presence of amorphous phases resulting from local melting, which is also associated with the thermal runaway mechanism. Finally, an experimental setup for in-situ TEM flash sintering analysis was developed, where changes in the structure of electron transparent samples could be detected and monitored during the application of an electric field to simulate FS at room temperature, (Figure 1).  Figure 1 - TEM images of La0.75Sr0.25CrO3 a) before and b) after flash sintering.  Acknowledgements: Fátima Zorro acknowledges the financial support of FCT – Portugal, through the studentship 2021.05950.BD of the 2021 Call for Ph.D. Studentships. This work was supported by FCT, through IDMEC, under LAETA, project UIDB/50022/2020. [1] N. Yan et al., “Ethanol-Induced Flash Sintering of ZnO Ceramics at Room Temperature,” Materials (Basel), vol. 15, no. 3, pp. 1–9, 2022. [2] Y. Zhu et al., “Gas-discharge induced flash sintering of YSZ ceramics at room temperature,” J. Adv. Ceram., vol. 11, no. 4, pp. 603–614, 2022. [3] R. Catlow and A. Walsh, “Semiconducting oxides,” J. Phys. Condens. Matter, vol. 23, no. 33, pp. 2010–2011, 2011. [4] R. Serrazina, A. Tkach, L. Pereira, A. M. O. R. Senos, and P. M. Vilarinho, “Flash Sintered Potassium Sodium Niobate: High-Performance Piezoelectric Ceramics at Low Thermal Budget Processing,” Materials (Basel), vol. 15, no. 19, 2022. [5] R. Serrazina, J. S. Dean, I. M. Reaney, L. Pereira, P. M. Vilarinho, and A. M. O. R. Senos, “Mechanism of densification in low-temperature FLASH sintered lead free potassium sodium niobate (KNN) piezoelectrics,” J. Mater. Chem. C, vol. 7, no. 45, pp. 14334–14341, 2019. 

Understanding Flash Sintering of Semiconductor Oxide Materials at the Nano- Atomic Scale

https://dc.engconfintl.org/cgi/viewcontent.cgi?filename=0&article=1041&context=efe_advancedmaterials_iii&type=additional

Understanding Flash Sintering of Semiconductor Oxide Materials at the Nano- Atomic Scale

Abstract

Similar works

Full text

Available Versions

Engineering Conferences International