Fabrication and Characterization of Ce-Doped Gd2Zr2O7 Ceramics as Simulated Waste Forms for Treating Pu

2015 ◽  
Vol 737 ◽  
pp. 639-641 ◽  
Author(s):  
Yan Kai Yang ◽  
Yi Xie ◽  
Xi Rui Lu
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Atmospheric Pressure ◽  
Pyrochlore Structure ◽  
Fluorite Structure ◽  
Waste Forms ◽  
Simulated Waste ◽  
Fabrication And Characterization ◽  
Structure And Microstructure

In order to investigate the disposal of plutonium by Gd2Zr2O7, Ce-doped Gd2Zr2O7 were fabricated by high temperature solid state reaction at 1500 °C under atmospheric pressure for 72 h. XRD and SEM studies were exploited to characterize the crystal structure and microstructure of the synthetic samples. The results revealed that Gd2Zr2O7 shows a single pyrochlore structure while Gd2Ce2O7 exhibit a defective fluorite structure. The microstructure of the samples was relatively dense, and the grain size was in the range of 3 - 6 μm.

Fabrication of Pyrochlore Gd2Zr2O7 by High Temperature Solid State Reaction

2014 ◽  
Vol 1061-1062 ◽  
pp. 87-90 ◽  
Author(s):  
Long Fan ◽  
Yi Xie ◽  
Xiao Yan Shu
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
High Temperature ◽  
Solid State ◽  
Solid State Reaction ◽  
Atmospheric Pressure ◽  
Raw Materials ◽  
Pyrochlore Structure ◽  
Structure And Microstructure ◽  
Sem Studies

In order to investigate the fabrication of pyrochlore Gd2Zr2O7, Gd2O3 and ZrO2 were used as raw materials in the process. Pyrochlore Gd2Zr2O7 were fabricated by high temperature solid state reaction at 1100 – 1600 °C under atmospheric pressure for 72 h. XRD and SEM studies were exploited to characterize the crystal structure and microstructure of the synthetic samples. The results revealed that Gd2Zr2O7 with a single pyrochlore structure was fabricated successfully at 1500 °C. The microstructure of the sample was uniform and dense, and the grain size was in the range of 1 - 3 μm.

scholarly journals Synthesis and Characterization of Thermal Properties of Type Eu2O3-ZrO2 Sinters

2016 ◽  
Vol 61 (2) ◽  
pp. 1121-1128 ◽  
Author(s):  
S. Jucha ◽  
G. Moskal ◽  
M. Mikuśkiewicz
Keyword(s):  
High Temperature ◽  
Pyrochlore Structure ◽  
Ceramic Materials ◽  
Fluorite Structure ◽  
Sintering Process ◽  
Mechanical Mixing ◽  
Potential Alternative ◽  
Homogenization Methods ◽  
New Phase

Abstract The oxides with pyrochlore or defected fluorite structure are a potential alternative ceramic materials for now widely used yttria-stabilized zirconia 8YSZ in the application for the insulation layer of thermal barrier coatings systems. This paper presents a procedure of synthesis of europium zirconate of Eu2Zr2O7 type, by the method of high temperature sintering under pressure. The analysis of the effect of the powders` homogenization methods on homogeneity of final sintered material showed that the highest homogeneity can be obtained after mechanical mixing in alcohol. Moreover, the DSC investigation carried out on a mixture of powders before the sintering process and on the material after high temperature sintering under pressure, suggest the synthesis of a new phase an europium zirconate Eu2Zr2O7 with the pyrochlore structure. Obtained phase was characterized by stability over the entire range of tested temperature, i.e. to 1450°C. The resulting material based on europium zirconate has a lower coefficient of thermal diffusivity than the now widely used 8YSZ.

Synthesis and Characterization of Mg2Si Thermoelectric Material

2013 ◽  
Vol 802 ◽  
pp. 213-217 ◽  
Author(s):  
Chalida Nakhowong ◽  
Teerawut Sumpao ◽  
Tosawat Seetawan
Keyword(s):  
Crystal Structure ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Argon Atmosphere ◽  
Synthesis And Characterization ◽  
Mixed Powder ◽  
Reaction Method ◽  
Cubic Structure ◽  
Structure And Microstructure

The Mg2Si compound was synthesized by the solid state reaction method. The powder precursors of Mg and Si were thoroughly mixed in ballmilling for 24 hr in an argon atmosphere. Mixed powder was pressed at 170MPa and sintered at 800 °C for 6 hr in an argon atmosphere. The sinter powder was crushed in mortar for 1 hr. The crystal structure and microstructure were measured and observed by using XRD and SEM. The microstructure and the crystal structure were analyzed. TheMg2Si shows single phase, cubic structure and particle size about 1-10 mm.

scholarly journals Rapid Synthesis and Chemical Durability of Gd2- x Nd x Zr2O7 (0.0 ≤ x ≤ 2.0) Sub-Micron Ceramics as Nuclear Waste Forms

2020 ◽  
Author(s):  
Kui Liu ◽  
Kuibao ZHANG ◽  
Ting DENG ◽  
Jianjun ZENG ◽  
Daimeng CHEN ◽  
...  
Keyword(s):  
Grain Size ◽  
Solvothermal Method ◽  
Pyrochlore Structure ◽  
Fluorite Structure ◽  
Nanocrystalline Powders ◽  
Release Rates ◽  
Chemical Furnace ◽  
Sample Density ◽  
Nuclear Waste Forms ◽  
Trivalent Actinide

Abstract In this work, Nd3+ was used as a surrogate and it was incorporated into Gd2Zr2O7 nanocrystalline ceramics to simulate the immobilization of trivalent actinide elements. A series of Gd2 − xNdxZr2O7 (0.0 ≤ x ≤ 2.0) nanocrystalline powders were fabricated by solvothermal method, and then Gd2 − xNdxZr2O7 sub-microncrystalline ceramics were prepared by sintering via self-propagating chemical furnace plus quick pressing (SCF/QP). All powders are in defective fluorite structure, and Nd doping hardly change the powder grain size. After analyzing the sintered ceramics, it can be found that the transition from defective fluorite structure to pyrochlore structure occurs when x ≥ 1.5. The sample density decreases with elevated Nd content, while the grain size gradually enlarges. Besides, the normalized release rates of Nd and Zr elements in the Nd2Zr2O7 waste form are kept in low values (below 10− 5 g•m− 2•d− 1), which exhibits its excellent aqueous stability.

Fabrication and Characterization of Li4SiO4 Ceramic Pebbles Doped with Y2O3 and Nb2O5

2018 ◽  
Vol 281 ◽  
pp. 28-33 ◽  
Author(s):  
Man Wang ◽  
Mao Qiao Xiang ◽  
Ying Chun Zhang
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Grain Growth ◽  
Fusion Reactor ◽  
Comprehensive Properties ◽  
Tritium Breeder ◽  
Fabrication And Characterization ◽  
Tritium Release ◽  
Better Than

Tritium breeder blanket has been considered as one of the most important components of thermonuclear fusion reactor. Recently, Li4SiO4has been regarded as one of the favored ceramics breeders as it exhibits excellent tritium release properties. In order to further improve the comprehensive properties of Li4SiO4pebbles, the grain size and crush load of Li4SiO4pebbles doped with Y2O3and Nb2O5were systematically studied in this work. The results showed that the relative density of Li4SiO4pebbles was increased to 87.2% and the crush load was increased from 43N to 48N when Y2O3doping was used. In view of inhibiting grain growth and increasing the crush load and relative density of Li4SiO4pebbles, the effect of Nb2O5doping was better than that of Y2O3doping.

Structure and Ionic Conductivity of Ln2Zr2O7-Type Rare Earth Zirconates

2007 ◽  
Vol 336-338 ◽  
pp. 420-423 ◽  
Author(s):  
Rui Zhang ◽  
Qiang Xu ◽  
Wei Pan ◽  
Chun Lei Wan ◽  
Long Hao Qi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Solid State ◽  
Ionic Conductivity ◽  
Single Phase ◽  
Complex Impedance ◽  
Pyrochlore Structure ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
X Ray

Three rare earth zirconates (Sm2Zr2O7, Gd2Zr2O7 and Er2Zr2O7) were prepared by solid state reaction. The crystal structure and ionic conductivity of these zirconates were characterized by X-ray diffraction (XRD) and complex impedance spectroscopy. The results show that Sm2Zr2O7 exhibits single-phase pyrochlore structure and Er2Zr2O7 exhibits single-phase fluorite structure, while Gd2Zr2O7 has pyrochlore and fluorite structure. Among three zirconates, the ionic conductivity of Sm2Zr2O7 is highest, while that of Er2Zr2O7 is lowest.

Fabrication and Characterization of AgCoO2 Delafossite by Cation Exchange Process

2014 ◽  
Vol 602-603 ◽  
pp. 11-14
Author(s):  
Xiu Li Feng ◽  
Xiao Jiang Liu ◽  
Yong Qiang Yuan
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Cation Exchange ◽  
Exchange Process ◽  
Single Particles ◽  
Effect Factors ◽  
Sem Images ◽  
Preparation Conditions ◽  
Fabrication And Characterization

A new method to synthesize AgCoO2 delafossite powder with AgNO3 and LiCoO2 by the cation exchange solid state reaction at an atmospheric press has been presented. The effect factors such as moral ratio Ag/Li, reaction time, reaction temperature on the production were discussed systematically and the optimized preparation conditions were obtained. The crystal structure of AgCoO2 from XRD is monoclinic. SEM images showed that AgCoO2 is sheet in shape,single particle size is about 100nm and many single particles swam to form irregular polygon agglomerates.

scholarly journals Microstructural Characterization of Glass and Ceramic Simulated Waste Forms

1980 ◽  
pp. 249-254
Author(s):  
Thomas J. Headley ◽  
John T. Healey ◽  
Paul F. Hlava ◽  
Michael J. Kupfer ◽  
Denis M. Strachan
Keyword(s):  
Microstructural Characterization ◽  
Waste Forms ◽  
Simulated Waste
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