The effect of processing on the thermal diffusivity of MgO–Nd2Zr2O7 composites for inert matrix materials

Yates, Samantha J.; McClellan, Kenneth J.; Nino, Juan C.

doi:10.1016/j.jnucmat.2009.06.006

Cited by 20 publications

(4 citation statements)

References 30 publications

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“…Ceramics with pyrochlore structure have been identified as potential waste form materials for the immobilization of actinides present in radioactive waste and as inert matrix materials for actinide transmutation. [5][6][7] As nuclear waste forms materials, structures based on titanate, stannate and zirconate pyrochlore have been investigated extensively. [8][9][10][11][12][13][14] In contrast to titanate pyrochlore which are susceptible to radiation induced amorphization, the zirconate ceramics show remarkable resistance to amorphization under ion beam irradiation.…”

Section: Introductionmentioning

confidence: 99%

Nd and Ce simultaneous substitution driven structure modifications in Gd2−xNdxZr2−yCeyO7

Sijin

Ding

Shu

et al. 2015

Journal of the European Ceramic Society

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Section: Introductionmentioning

confidence: 99%

Nd and Ce simultaneous substitution driven structure modifications in Gd2−xNdxZr2−yCeyO7

Sijin

Ding

Shu

et al. 2015

Journal of the European Ceramic Society

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“…(Yb x Nd 1-x ) substituent confers to the studied (Yb x Nd 1-x ) 2 Zr 2 O 7 pyrochlores a structure with a lattice parameter which is close to that of Sm. One can observe the presence of typical super-lattice peaks at 2θ values of about 14° (111), 28° (311), 29° (222), 33° (400), 37° (331), 45° (511), 48° (440), 50° (531), 57° (622), 60° (444) and 71° (800), using Cu Ka radiation [35,48,[52][53][54][55][56].…”

Section: Phase Identification and Microstructurementioning

confidence: 99%

Synthesis and Characterization of a Neodymium Zirconate Pyrochlore Doped with Ytterbium: (YbxNd1-x)2Zr2O7 (x = 0.1, 0.25 and 0.4)

Kamel¹,

Moudir²,

Kamel³

et al. 2013

JMSE-B

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This study deals with the solid state synthesis of neodymium zirconates, doped with ytterbium, with the chemical formulas of: (Yb x Nd 1-x) 2 Zr 2 O 7 , (x = 0.1, 0.25 and 0.4). These materials are proposed as high-level radioactive waste confinement materials. Neodymium is employed as an actinide surrogate. The synthesis process consists in successive calcination steps at: 600, 1,200, 1,300 and 1,400 °C. The end-products have a sintered density of 6,368, 6,543 and 6,674 kg/m 3 , for: (Yb 0.1 Nd 0.9) 2 Zr 2 O 7 , (Yb 0.25 Nd 0.75) 2 Zr 2 O 7 and (Yb 0.4 Nd 0.6) 2 Zr 2 O 7 , respectively. The pyrochlores X-ray diffraction patterns of an fcc pyrochlore type lattice: Fd-3m, have been identified. The differential thermal analysis of these zirconates confirms there thermal stability. The materials do not show any phase transition against heating, until 1,650 °C, and under cooling. For the whole, the measured microhardnesses (< 120 HV) and fracture toughness' (< 1.57 × 10 6 N/m 2) reveal a brittle mechanical behaviour of the studied pyrochlores.

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“…Thermal conductivity (k) is proportional to thermal diffusivity (), specific heat (C p ), and sample density (). Thermal diffusivity () usually increases as density increases [9]. Therefore, the overall thermal conductivity increases with sample density.…”

Section: Normalized Mass Loss Rate and Temperature Dependencementioning

confidence: 99%

Hydrothermal Corrosion of Magnesia-Pyrochlore Composites for Inert Matrix Materials

Yates

Nino

2009

Journal of Composite Materials

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The corrosion behavior of MgONd 2 Zr 2 O 7 cercer composites was investigated under hydrothermal conditions at 300 C and saturation pressure. It was found that corrosion resistance was microstructure dependent in terms of MgO contiguity and homogeneity. The inhomogeneous composites completely dissolved in less than 1 h showing poor hydration resistance similar to MgO. The homogeneous composites exhibited an improved hydration resistance and the corrosion was primarily limited to the surface. The normalized mass loss (NML) was proportional to the corrosion time and the NML rate increased with MgO volume fraction. The corrosion process followed an Arrhenius relationship and the apparent activation energy was calculated to be $3941 kJ/mol. It is suggested that the mass loss of the MgONd 2 Zr 2 O 7 composites is mainly governed by hydration of MgO and the NML rate is enhanced by contiguity of MgO. A desirable microstructure with enhanced corrosion resistance is viewed to have minimum contiguity of MgO, good homogeneity, and large MgO grain size (minimizing grain boundaries).

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The effect of processing on the thermal diffusivity of MgO–Nd2Zr2O7 composites for inert matrix materials

Cited by 20 publications

References 30 publications

Nd and Ce simultaneous substitution driven structure modifications in Gd2−xNdxZr2−yCeyO7

Nd and Ce simultaneous substitution driven structure modifications in Gd2−xNdxZr2−yCeyO7

Synthesis and Characterization of a Neodymium Zirconate Pyrochlore Doped with Ytterbium: (YbxNd1-x)2Zr2O7 (x = 0.1, 0.25 and 0.4)

Hydrothermal Corrosion of Magnesia-Pyrochlore Composites for Inert Matrix Materials

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