Effect of sintering atmosphere on the hardness of ThO2

Thomas Cardinaels; Jelle Van Eyken; Jean-Louis Puzzolante; Marc Verwerft; Angela Baena; Koen Binnemans

doi:10.1016/j.jnucmat.2016.05.025

Effect of sintering atmosphere on the hardness of ThO2

Thomas Cardinaels, Jelle Van Eyken, Jean-Louis Puzzolante, Marc Verwerft, Angela Baena, Koen Binnemans

Research output › peer-review

Abstract

The hardness and toughness of ThO2 sintered under reducing and oxidizing conditions has been investigated and, quite unexpectedly, a significant difference in hardness was observed for the entire range of porosities studied. Reducing conditions systematically yielded higher hardness values than oxidizing conditions. Extrapolated to zero porosity, the hardness for ThO2 is H0 = 10.5 ± 0.3 GPa for oxidizing conditions and H0 = 12.4 ± 0.7 GPa for reducing conditions. Toughness values have been derived from Vickers indentations; differences in toughness were insignificant and only a single value is proposed: KIC = 0.97 ± 0.12 MPa √m. The difference in hardness is attributed to the presence of point defects, also acting as color centers and causing grey coloration of ThO2 sintered under reducing conditions. Furthermore, and of interest for nuclear fuel production, is the finding that ThO2 sintered under reducing conditions is significantly easier to grind compared to material sintered under oxidizing conditions.

Original language	English
Pages (from-to)	222-227
Number of pages	6
Journal	Journal of Nuclear Materials
Volume	477
DOIs	https://doi.org/10.1016/j.jnucmat.2016.05.025
State	Published - 15 Aug 2016

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@article{c5c25f701b0e446695e7a40efdc547c9,

title = "Effect of sintering atmosphere on the hardness of ThO2",

abstract = "The hardness and toughness of ThO2 sintered under reducing and oxidizing conditions has been investigated and, quite unexpectedly, a significant difference in hardness was observed for the entire range of porosities studied. Reducing conditions systematically yielded higher hardness values than oxidizing conditions. Extrapolated to zero porosity, the hardness for ThO2 is H0 = 10.5 ± 0.3 GPa for oxidizing conditions and H0 = 12.4 ± 0.7 GPa for reducing conditions. Toughness values have been derived from Vickers indentations; differences in toughness were insignificant and only a single value is proposed: KIC = 0.97 ± 0.12 MPa √m. The difference in hardness is attributed to the presence of point defects, also acting as color centers and causing grey coloration of ThO2 sintered under reducing conditions. Furthermore, and of interest for nuclear fuel production, is the finding that ThO2 sintered under reducing conditions is significantly easier to grind compared to material sintered under oxidizing conditions.",

keywords = "Fracture-toughness, Thermodynamic porperties, Thorium-dioxide, Irradation, Fuel, Performance, Porosity, Pellets, System, Oxide",

author = "Thomas Cardinaels and {Van Eyken}, Jelle and Jean-Louis Puzzolante and Marc Verwerft and Angela Baena and Koen Binnemans",

note = "Score=10",

year = "2016",

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doi = "10.1016/j.jnucmat.2016.05.025",

language = "English",

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pages = "222--227",

journal = "Journal of Nuclear Materials",

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T1 - Effect of sintering atmosphere on the hardness of ThO2

AU - Cardinaels, Thomas

AU - Van Eyken, Jelle

AU - Puzzolante, Jean-Louis

AU - Verwerft, Marc

AU - Baena, Angela

AU - Binnemans, Koen

N1 - Score=10

PY - 2016/8/15

Y1 - 2016/8/15

N2 - The hardness and toughness of ThO2 sintered under reducing and oxidizing conditions has been investigated and, quite unexpectedly, a significant difference in hardness was observed for the entire range of porosities studied. Reducing conditions systematically yielded higher hardness values than oxidizing conditions. Extrapolated to zero porosity, the hardness for ThO2 is H0 = 10.5 ± 0.3 GPa for oxidizing conditions and H0 = 12.4 ± 0.7 GPa for reducing conditions. Toughness values have been derived from Vickers indentations; differences in toughness were insignificant and only a single value is proposed: KIC = 0.97 ± 0.12 MPa √m. The difference in hardness is attributed to the presence of point defects, also acting as color centers and causing grey coloration of ThO2 sintered under reducing conditions. Furthermore, and of interest for nuclear fuel production, is the finding that ThO2 sintered under reducing conditions is significantly easier to grind compared to material sintered under oxidizing conditions.

AB - The hardness and toughness of ThO2 sintered under reducing and oxidizing conditions has been investigated and, quite unexpectedly, a significant difference in hardness was observed for the entire range of porosities studied. Reducing conditions systematically yielded higher hardness values than oxidizing conditions. Extrapolated to zero porosity, the hardness for ThO2 is H0 = 10.5 ± 0.3 GPa for oxidizing conditions and H0 = 12.4 ± 0.7 GPa for reducing conditions. Toughness values have been derived from Vickers indentations; differences in toughness were insignificant and only a single value is proposed: KIC = 0.97 ± 0.12 MPa √m. The difference in hardness is attributed to the presence of point defects, also acting as color centers and causing grey coloration of ThO2 sintered under reducing conditions. Furthermore, and of interest for nuclear fuel production, is the finding that ThO2 sintered under reducing conditions is significantly easier to grind compared to material sintered under oxidizing conditions.

KW - Fracture-toughness

KW - Thermodynamic porperties

KW - Thorium-dioxide

KW - Irradation

KW - Fuel

KW - Performance

KW - Porosity

KW - Pellets

KW - System

KW - Oxide

UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/35748018

U2 - 10.1016/j.jnucmat.2016.05.025

DO - 10.1016/j.jnucmat.2016.05.025

M3 - Article

SN - 0022-3115

VL - 477

SP - 222

EP - 227

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

ER -