JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2022
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IF 6.364
Xiaowen Hu,Jinwu Chen,Jie Li,Huaicheng Xiang,Ying Tang,Liang Fang
Two zircon-structured ceramics AEuV 2 O 8 (A = Bi, La) were prepared with optimal sintering temperatures of 900 °C and 1375 °C, respectively. They exhibited sharp contrast performances with medium ε r ∼ 28.7 ± 0.1, Q × f ∼ 14,000 ± 300 GHz, and large positive τ f ∼ 75.7 ± 2.0 ppm/°C for BiEuV 2 O 8 , whereas low ε r ∼ 10.4 ± 0.1 Q × f ∼ 25,100 ± 300 GHz, and negative τ f ∼ − 40.7 ± 2.0 ppm/°C for LaEuV 2 O 8 . The rattling effect at the A-site was more dominant in determining microwave dielectric properties than that of compressed V 5+ at the B-site. It resulted in the higher ε r , lower Q × f and τ ε , and larger τ f of BiEuV 2 O 8 than those of LaEuV 2 O 8 . Besides, their Q × f was related with the relative density, bond valence and FWHM of the B 1 g Raman mode.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF NUCLEAR MATERIALS
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2017
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IF 2.048
Kuibao Zhang,Dan Yin,Le Peng,Jingjun Wu,Jiali Xue
In this study, zirconolite/Mo composites were rapidly synthesized by a self-propagation reaction that uses MoO 3 as the oxidant accompanied with pressing. Zirconolite is one of the several materials that are being researched as host for lanthanides and actinides in nuclear waste . Nd was used in this study as a surrogate for actinides and was substituted into zirconolite at a stoichiometric ratio to charge balance the Ca and Zr sites (nominal formulation of Ca 1-x Zr 1-x Nd 2x Ti 2 O 7 ). Perovskite , zirconia, and rutile were generated as the minor phases with the addition of Nd 2 O 3 . The XRD results demonstrated that the Nd 2 O 3 loading is approximately 30 wt%. Nd was mainly incorporated into the lattice structure of zirconolite and perovskite. A 42-day leaching test of the Nd-bearing zirconolite/Mo composite showed that the computed normalized leaching rates for Ca and Nd at fairly low values of 9.02 × 10 −2 and 2.10 × 10 −4 g m −2 d −1 , respectively.
研究领域:
材料科学
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核废物管理
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
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2018
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IF 2.524
Weimin Li,Faqin Dong,Liang Bian,Hao Zou,Mianxin Song
In this study, Ce-doped zirconolite was synthesized through high-temperature solid-state reaction at 1250 °C in air for 96 h. The crystal phase, microstructure and valence transition were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Phase relations of CaZr 1– x Ce x Ti 2 O 7 systems were determined by XRD analyses and Rietveld refinements . Four different phases are identified, namely zirconolite, perovskite , pyrochlore, and cerianite. The phase transformation (2M-zirconolite → 4M-zirconolite → Ce-pyrochlore) is caused by cations rearrangement as cerium content increases. The solubility limit of cerium ions in CaZr 1– x Ce x Ti 2 O 7 system is estimated to be approximately 0.80. Under sintering air atmosphere, partial reduction of Ce 4+ in Ce 3+ is detected in Ce 3d XPS spectra, and the ratio of Ce 3+ and Ce 4+ significantly decreases as cerium content increases.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NUCLEAR MATERIALS
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2025
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IF 3.2
Shiyin Ji,Yanhao Song,Xiuhua Ji,Yanxia Wei,Changzhong Liao,Yuhong Li,Tao duan
Zirconolite ceramics are emerging as the promising immobilization matrix for high-level radioactive waste (HLW) in deep geological repositories. The radiation stability is a critical factor in assessing their long-term safety. In this work, three zirconolite polytypes of zirconolite-2M, zirconolite-3O and zirconolite-4M were irradiated by 1.5 MeV Xe 10+ (heavy) and 400 keV Ne 4+ (light) ions at fluences of 1 × 10 14 to 2 × 10 15 ions/cm 2 and 1 × 10 15 to 1 × 10 16 ions/cm 2 , respectively. The irradiation damage was systematically studied using GIXRD, Raman and XPS. Results showed that zirconolite-4M had marginally higher radiation resistance than zirconolite-2M, which slightly outperformed zirconolite-3O under heavy ion irradiation. For light ion irradiation, zirconolite-3O demonstrated comparable or slightly better stability than zirconolite-2M. However, Direct comparisons of radiation tolerance were complicated by variations in displacement per atom (dpa) at equivalent fluences. In addition, the phase evolution of zirconolite to cubic defect-fluorite derivative structures (pyrochlore or defect-fluorite) was observed during the amorphization process for the three zirconolite polytypes, irrespective of the ion type (heavy or light). Zirconolite-2M and -3O reached near-complete amorphization at approximately 4 dpa, while zirconolite-4M predominantly retained its crystalline structure even at higher radiation doses (2.5 dpa for light ions and 3.78 dpa for heavy ions). These findings provide critical insights into the design of HLW matrices and the evaluation of their radiation stability, contributing to the development of safer and more durable waste forms for long-term geological storage.
研究领域:
材料科学
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核能工程
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辐射物理
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2024
·
IF 5.1
Xiuhua Ji,Yanhao Song,Jiarun Wang,Yi Ding,Shiyin Ji,Tao Duan
Zirconolite and pyrochlore have been considered as the potential immobilization matrix materials of minor actinides due to their high solubility, radiation tolerance and chemical durability. In this work, a series of Ca 1-x Ho 2x Zr 1-x Ti 2 O 7 (0.1 ≤ x ≤ 1.0) ceramics were prepared by solid state synthesis and sintering at 1400 °C for 48 h twice. Powder X-ray Diffraction (XRD), Backscattered Scanning Electron Microscopy with Energy-Dispersive X-ray spectroscopy (BSEM-EDX), Transmission Electron Microscopy (TEM) were employed to investigate the phase evolution, solubility, and substitution mechanism of Ho. The results displayed that zirconolite-2M would be transformed to zirconolite-4M and then to pyrochlore with increasing Ho concentration. The initial phase transformation of zirconolite-2M to zirconolite-4M, subsequently zirconolite-4M to pyrochlore were observed in x = 0.2 and 0.4 samples, respectively. Zirconolite-4M could be synthesised at x = 0.38 sample with trace perovskite. Moreover, the semi-quantitively solubility limits of Ho in zirconolite-2M and zirconolite-4M were determined to be 27 and 41.5 at.%, respectively. Single-phase pyrochlore were fabricated after 70 at.%. In addition, the novel substitution mechanism was revealed by Rietveld refinement with Ho preferentially replacing the Ca of zirconolite-2M so that some replaced Ca occupied vacant Zr site. For pyrochlore, Ho, Ca and Zr occupied A site (16d) and Ti entered in B site (16c). The findings would provide more insights into zirconolite–pyrochlore ceramic system.
研究领域:
材料科学
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核化学与放射化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
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IF 3.83
Zi-Jun Wei,Weichao Bao,Shi-Kuan Sun,Lewis R. Blackburn,Sheng-Heng Tan,Laura J. Gardner,Wei-Ming Guo,Fangfang Xu,Neil C. Hyatt,Hua-Tay Lin
Praseodymium-doped zirconolite ceramics targeting nominal composition Ca 1-x Pr x ZrTi 2-5x/3 Al 5x/3 O 7 (x ≤ 0.20, Δx = 0.05) were fabricated by a mixed oxide solid state reaction, at 1350 °C in air for 20 h. Praseodymium (Pr) was employed as a surrogate for neptunium (Np), with Al 3+ co-accommodated to provide charge balance. High-resolution transmission electron microscopy and electron diffraction analyses confirmed that zirconolite crystallised as the 2M monoclinic polytype throughout the phase evolution, with no evidence of transformation to other polytype structures. Phase assemblage and microstructural data were consistent with zirconolite occupying a high fraction of the phase assemblage (> ca . 93 wt.%), alongside a minor secondary perovskite phase at all levels of targeted Pr incorporation. Despite this, it was demonstrated near theoretical density formed through a solid-state fabrication route, and we therefore propose that, through analogy with the corresponding Pr solid solution, zirconolite may be a suitable candidate for the immobilisation of Np-bearing wastes.
研究领域:
材料科学
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核废料管理
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2023
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IF 5.2
Junling Yu,Feng Jiang,Jianmin Liu,Tao Wang,Xiaojun Zhang,Quan Zhang,Rongchi Zhang,Qian Wu,Qing Hu,Yun Yu,Guo Feng
Novel (Cr,V)–ZrSiO 4 jewel green pigments with good near-infrared reflection performance were prepared by in-situ mineralization at a low temperature of 900 °C. The synthesized pigments were characterized through XRD , FE-SEM, TEM, UV–Vis–NIR, XPS, and CIE L*a*b* colorimetry. The results show that Cr–V co-doping into the zircon lattice can effectively promotes the synthesis of zircon, and significantly produce a coloring effect from blue to jewel green and then to dark green with the increase of Cr/Si mole ratio from 0.025 to 0.4. The optimized Cr/Si is 0.2, showing excellent color rendering performance ( L * = 56.69, a * = -18.52, b * = -9.28). The electron transitions of the (Cr,V)–ZrSiO 4 pigments exhibits broadband emission and shifts to longer wavelength (530 nm) relative to V–ZrSiO 4 with Cr/Si mole ratio of 0, corresponding to the jewel green region. And the pigments possess good near-infrared reflectance in the range of 700–2500 nm. The properties especially excellent near-infrared reflection performance make it promising functional pigment for energy-saving and health.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）