Controlled current-rate AC flash sintering of uranium dioxide

JOURNAL OF NUCLEAR MATERIALS

卷:547

Article

Neto, R. R. Ingraci¹  McClellan, K. J.¹  Byler, D. D.¹  Kardoulaki, E.¹ 

[1] Los Alamos Natl Lab, Mat Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA

关键词: Field assisted sintering;    Flash sintering;    Uranium dioxide;    Nuclear fuel;    Master sintering curve;    Anisotropic shrinkage;   

DOI  :  10.1016/j.jnucmat.2021.152780

来源: Elsevier

【 摘 要 】

Uranium dioxide (UO2) pellets with controlled microstructures were densified up to 93.4% of their theoretical density in less than 25 minutes at a furnace temperature of 873 K, utilizing controlled current-rate alternating current (AC) flash sintering (FS). Using this AC-FS method it was possible to control the sintering rate and thermal gradients, resulting in dense pellets with no appreciable hourglassing and good mechanical integrity. Moreover, the apparent sintering activation energy for FS and for conventionally sintered samples was estimated to be 108 kJ mol(-1) and 380 kJ mol(-1), respectively using the master sintering curve method. The apparent activation energy for FS was remarkably close to those reported in the literature for spark plasma sintering of UO2. Both these field assisted sintering methods utilize fast heating rates and electrical effects that are likely enhancing the grain boundary diffusion mechanism. Finally controlled current-rate AC-FS has been demonstrated as a technological advancement, capable of producing ceramic nuclear fuels in a fraction of the conventional processing time. (C) 2021 Elsevier B.V. All rights reserved.

【 授权许可】

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