The effect of atmosphere on the flash-sintering of nanoscale titania ceramics

SCRIPTA MATERIALIA

卷:199

Article

Wang, Qizhong¹  Watts, Connor S.¹  Athanasiou, Christos E.¹  Dai, Zhenghong¹  Hu, Mingyu¹  Sheldon, Brian W.¹  Padture, Nitin P.¹ 

[1] Brown Univ, Sch Engn, Providence, RI 02912 USA

关键词: Titania;    Flash-sintering;    Atmosphere;    Microstructure;    Electrical conductivity;   

DOI  :  10.1016/j.scriptamat.2021.113894

来源: Elsevier

【 摘 要 】

Flash-sintering is a promising approach for the ultra-rapid densification of ceramics at low furnace temperatures under an applied electric field. Here we have studied the effect of atmosphere on the flash-sintering of titania (TiO2) nanopowders under an applied electric field of 400 V.cm(-1), and find a dramatic reduction in the flash-onset furnace temperature (T-F), from 648 degrees C in air to 239 degrees C in argon (Ar). The reduced T-F is close to the TiO2 Debye-temperature limit. This is attributed to a combination of nanocrystalline nature of the TiO2 powder and the O-2-lean Ar atmosphere, resulting in enhanced electrical-conductivity characteristics. The reduced T-F also results in finer, uniform average grain sizes (360 nm to 190 nm) and lower, uniform porosity (0.5% to 1.4%), going from the anode to the cathode. In contrast, in air the corresponding average-grain-size range is 9.6 mu m to 1.3 mu m and the porosity range is 1.9% to 3.3%. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

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