Browsing by Author "Zhang, ZM"

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    Cation antisite disorder in uranium-doped gadolinium zirconate pyrochlores
    (Elsevier, 2014-09-01) Gregg, DJ; Zhang, ZM; Thorogood, GJ; Kennedy, BJ; Kimpton, JA; Griffiths, GJ; Guagliardo, PR; Lumpkin, GR; Vance, ER
    The incorporation of uranium into gadolinium zirconate (Gd2Zr2O7) is investigated by synchrotron X-ray powder diffraction and X-ray absorption near-edge structure (XANES) spectroscopy. The results suggest that the uranium cation is largely located on the pyrochlore B-site instead of the targeted A-site. Cation disorder in Gd2Zr2O7 and U-doped Gd2Zr2O7 is investigated by positron annihilation lifetime spectroscopy (PALS) which demonstrates the absence of cation vacancies in these systems. This work provides direct evidence for cation antisite (A- and B-site mixing) disorder in U-doped and off-stoichiometric Gd2Zr2O7 pyrochlore. © 2014, Elsevier B.V.
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    Characterisation of alumina–silica films deposited by ALD
    (John Wiley & Sons, 2006-11-29) Prince, KE; Evans, PJ; Triani, G; Zhang, ZM; Bartlett, JR
    Atomic layer deposition (ALD) is a surface mediated chemical vapour deposition method that is capable of producing uniform films over large areas. In addition, the technique has been used to deposit highly conformal films on high aspect ratio structures. The applicability of any film deposition technique is dependent upon the properties of the final product. Many applications, such as optical coatings, require films of constant composition, low levels of impurities, and adherent interfaces. The latter may derive its strength from some form of interfacial mixing but this should not have an adverse effect on film performance. Dynamic SIMS (D-SIMS) offers a versatile tool for monitoring film and interface compositions as a function of depth. Sputtering the surface with Cs+ primary ions and detecting MCs+ secondary ions was found to offer the best analytical conditions for ALD films. In the present study, D-SIMS has been used to characterise films grown with silicon-containing precursors at temperatures between 200 and 300 °C. The D-SIMS results have been complemented with data obtained from XPS and an in situ quartz crystal microbalance (QCM). This combination of analytical techniques enabled the effects of different ALD process conditions to be evaluated. With this approach, it was possible to compare the relative amounts of Si in the films, determined by SIMS and XPS, with the mass gains measured for different pulsing sequences with the QCM. © 2006 John Wiley & Sons, Ltd.
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    Creating thin magnetic layers at the surface of Sb2Te3 topological insulators using a low-energy chromium ion beam
    (AIP Publishing, 2020-05-11) Cortie, DL; Zhao, WY; Yue, Z; Li, Z; Bake, A; Marenych, O; Pastuovic, Z; Nancarrow, M; Zhang, ZM; Qi, DC; Evans, PJ; Mitchell, DRG; Wang, XL
    The surfaces of Sb2Te3 topological insulator crystals were implanted using a 40 keV chromium ion beam. To facilitate uniform doping, the Sb2Te3 was passivated with a thin TiO2 film before the implantation step. The resulting chemical structure was studied using atomic-resolution transmission electron microscopy. A fluence of 7 × 1015 ions/cm2 at 40 keV lead to amorphization of the Sb2Te3 surface, with chromium predominantly incorporated in the amorphous layer. Heating to 200 °C caused the amorphous region to recrystallize and led to the formation of a thin chromium-rich interfacial layer. Near-edge x-ray absorption spectroscopy indicates a uniform valence state of Cr3+ throughout, with no evidence of metallic clustering. High-temperature superparamagnetic behavior was detected up to 300 K, with an increased magnetic moment below 50 K. © 2020 Author(s).
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    Crystal chemistry and ion-irradiation resistance of Ln2ZrO5 compounds with Ln = Sm, Eu, Gd, and Tb
    (John Wiley & Sons, Inc, 2021-12-22) Aughterson, RD; Lumpkin, GR; Zhang, ZM; Avdeev, M; Kong, L
    The previously unattained fabrication of single phase Ln2ZrO5 (Ln = Sm, Eu, Gd, and Tb) compounds via relatively low sintering temperature (1400°C) is achieved in this study using a coprecipitation method. The crystal structures have been investigated by neutron, synchrotron X-ray powder diffraction, and electron diffraction techniques. While the general long-range structure may be well described by the defect-fluorite type structure with Fm3m symmetry, electron diffraction has highlighted a complex underlying modulated structure that varies between each compound. These compounds have been tested for ion-irradiation response using in situ 1 MeV krypton ions and transmission electron microscopy characterization. None of the compounds undergo a crystalline to amorphous transition, even holding at 50 K. Both the underlying fluorite and modulated superstructures are little affected by the irradiation. However, some atomic rearrangements are observed in the postirradiated electron diffraction patterns for the Sm2ZrO5 specimen. © 2021 Commonwealth of Australia.
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    Crystal chemistry and structures of (Ca,U) titanate pyrochlores
    (Wiley-Blackwell, 2010-10-01) James, M; Carter, ML; Zhang, ZM; Zhang, YJ; Wallwork, KS; Avdeev, M; Vance, ER
    Analysis of multiphase (Ca,U) titanate pyrochlore samples produced under argon or in air, using laboratory X-ray powder diffraction (XRD) and electron microscopy revealed discrete pyrochlore phase compositions, together with either perovskite or rutile impurities. Investigations of these samples using diffuse reflectance and X-ray photoelectron spectroscopies revealed mixed U4+/U5+ oxidation states for argon-annealed samples and U5+/U6+ oxidation states for air-annealed samples. Single-phase (Ca1.25U4+0.25U5+0.50)Ti2O7 (argon) and (Ca1.40U5+0.60)(Ti1.90U6+0.10)O7 (air) compositions were synthesized and characterized using a combination of synchrotron X-ray and neutron powder diffraction. Severe intensity reduction of hkl odd XRD peaks from the sample produced in air was found to be the result of U6+ sharing the Ti site. The refined crystal structures for both single-phase samples were found to be consistent with the compositions and mixed oxidation states observed by the above spectroscopic measurements. Although the normalized uranium leach rate of the argon-annealed sample was found to be approximately twice that of the air-annealed sample, in 7-day Product Consistency Test the durability of both compounds with respect to leaching by water was found to be excellent. Ca releases were in the range of 0.01–0.03 g/L and U releases were <3 × 10−5 g/L. © 2010, Wiley-Blackwell.
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    Crystal chemistry and structures of uranium-doped gadolinium zirconates
    (Elsevier, 2013-07-01) Gregg, DJ; Zhang, YJ; Zhang, ZM; Karatchevtseva, I; Blackford, MG; Triani, G; Lumpkin, GR
    A series of uranium-containing gadolinium zirconate samples have been fabricated at 1450 °C in oxidizing, inert and reducing atmospheres. X-ray diffraction, Raman spectroscopy and transmission electron microscopy have been utilized to confirm adoption of pyrochlore or defect fluorite structures. X-ray diffraction allowed determination of the bulk averaged structure while Raman spectroscopy and transmission electron microscopy were used to determine ordering at the microdomain scale. Diffuse reflectance, X-ray absorption near edge structure and X-ray photoelectron spectroscopies indicated a predominantly U6+ oxidation state for all the air-sintered samples, even when Ca2+ or A-site vacancies were incorporated to charge balance for U4+, a mixed U5+/U6+ oxidation state was found for samples sintered in argon, while a mixed U4+/U5+ oxidation state occurred for sintering under N2–3.5%H2. This demonstrates a degree of uranium oxidation state control through sintering conditions, and the potential of using gadolinium zirconates as host materials for uranium in nuclear waste applications.© 2013, Elsevier B.V.
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    Crystal chemistry of the orthorhombic Ln2TiO5 compounds with Ln=La, Pr, Nd, Sm, Gd, Tb and Dy
    (Elsevier, 2015-07-01) Aughterson, RD; Lumpkin, GR; Thorogood, GJ; Zhang, ZM; Gault, B; Cairney, JM
    The crystal structures of seven samples of orthorhombic (Pnma) Ln2TiO5 compounds with Ln=La, Pr, Nd, Sm, Gd, Tb and Dy were refined by Rietveld analysis of synchrotron X-ray powder diffraction (S-XRD) data. With increasing size of the lanthanide cation, the lattice parameters increase systematically: c by only ~1.5% whereas both a and b by ~6% from Dy2TiO5 to La2TiO5. The mean Ti–O bond length only increases by ~1% with increasing radius of the Ln cation from Gd to La, primarily due to expansion of the pair of Ti–O3 bonds to opposite corners of the Ti–O5 square based pyramid polyhedra. For Dy2TiO5 and Tb2TiO5, a significant variation in Ti–O1 and Ti–O4 bond lengths results in an increased deformation of the Ti–O5 base. The particular configuration consists of large rhombic shaped tunnels and smaller triangular tunnels along the b axis, which have implications for defect formation and migration caused by radiation damage or the ionic conductivity. © 2017 Elsevier B.V.
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    Crystal growth and electronic structure of low-temperature phase SrMgF4
    (Elsevier B.V., 2016-04-01) Atuchin, VV; Goloshumova, AG; Isaenko, LI; Jiang, XX; Zhang, ZS; Zhang, ZM
    Using the vertical Bridgman method, the single crystal of low temperature phase SrMgF4 is obtained. The crystal is in a very good optical quality with the size of 10×7×5 mm3. Detailed photoemission spectra of the element core levels are determined by a monochromatic AlKa (1486.6 eV) X-ray source. Moreover, the first-principles calculations are performed to investigate the electronic structure of SrMgF4. A good agreement between experimental and calculated results is achieved. It is demonstrated that almost all the electronic orbitals are strongly localized and the hybridization with the others is very small, but the Mg–F bonds covalency is relatively stronger than that of Sr–F bonds. © 2015 Elsevier B.V.
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    Diffuse reflectance and x-ray photoelectron spectroscopy of uranium in ZrO2 and Y2Ti2O7.
    (Elsevier, 2010-05-01) Vance, ER; Zhang, YJ; Zhang, ZM
    Diffuse reflectance measurements were made over the wavenumber range of 4000–20,000 cm−1 at room temperature on monoclinic and stabilised ZrO2, together with Y2Ti2O7 having the pyrochlore structure, all of which were doped with U and sintered in various atmospheres. X-ray photoelectron spectroscopy measurements were also carried out on selected samples. In monoclinic and stabilised zirconia, U exhibited valence states of +4 and/or +5, depending on the sintering atmosphere and the presence of appropriate charge compensators. Using both diffuse reflectance and X-ray photoelectron spectroscopy, U was also observed as mainly U4+ and/or U5+ in U-doped Y2Ti2O7 sintered at 1400°C in air or Ar, although a small amount of U6+ also appeared to be present in some U-doped Y2Ti2O7 samples heated in air. © 2010, Elsevier Ltd.
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    Disorder by design: long- and short-range pyrochlore ordering
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2020-11-11) Mullens, BG; Kennedy, BJ; Zhang, ZM; Saura-Múzquiz, M
    Carbon-neutral energy generation is being developed in order to combat climate change. Two technologies of current interest, which are related to renewable and nuclear energy respectively, are next-generation oxygenion conductors for fuel cells and materials suitable for long-term storage and disposal of radioactive nuclear wastes [1-2]. Pyrochlores of the structure A2B2O7 have found immense applications in each of the above areas. Ionic conductors for fuel cells require flexibility and movement in their anionic sublattice, whereas the storage of radioactive nuclear wastes needs a robust lattice from which ions cannot escape. This is a seemingly contradiction in requirements. It is believed that the oxygen vacancies present in the pyrochlore structure allow for the development of short-range disorder, whilst keeping the long-range order intact [3]. The pyrochlore structure can be viewed as a superstructure of the defect-fluorite structure. The defect-fluorite structure (A2BO5) consists of a random distribution of cations and oxygen vacancies. However, by choosing A and B with a particular ionic radii ratio, the ordered pyrochlore superstructure may form under ambient conditions. This ordering of oxygen vacancies may be analysed using neutron powder diffraction and used to reason the enhanced properties and applications of pyrochlores [4]. The current work aims to characterise oxygen-vacancy disorder in defect pyrochlores so to enable the rational design of defect pyrochlores that are optimised for specific applications. We have done this by looking at ‘stuffed’ pyrochlores of the form A2(B2−xAx)O7−x/2 where the smaller B-type cation, in this case Ti4+, is progressively replaced by a larger A-type cation (Tm3+). We wish to determine whether controlling the disorder in the cation sublattice will allow us to tailor-make stuffed pyrochlores targeting specific applications across ionic conductivity, magnetism, photocatalysis and the storage of long-term radioactive waste. Series of stuffed pyrochlores have been synthesised using conventional solid-state methods and their longrange average structures characterised by Rietveld refinement against combined neutron and synchrotron X-ray diffraction data. The local short-range order has been characterised by Raman spectroscopy and XANES. Other measurements have also been performed regarding their applications, demonstrating a vast improvement in their ionic conductivity at high temperatures. These results will be presented, along with a judgement as to whether inducing certain types of disorder within the pyrochlore structure can lead to them being purposely engineered for specific applications. © 2020 The Authors
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    Gradual structural evolution from pyrochlore to defect-fluorite in Y2Sn2-xZrxO7: average vs local structure
    (ACS Publications, 2013-11-25) Zhang, ZM; Middleburgh, SC; de los Reyes, M; Lumpkin, GR; Kennedy, BJ; Blanchard, PER; Reynolds, EM; Jang, LY
    We have studied the long-range average and local structures in Y2Sn2−xZrxO7 (x = 0−2.0) using synchrotron X-ray powder diffraction and X-ray absorption spectroscopy, respectively, and by theoretical methods. While the diffraction data indicate a clear phase transition from ordered pyrochlore to disordered defectfluorite at x ∼ 1.0−1.2, X-ray absorption near-edge structure (XANES) results at the Zr L3- and Y L2-edges reveal a gradual structural evolution across the whole compositional range. These findings provide experimental evidence that the local disorder occurs long before the pyrochlore to defect-fluorite phase boundary, as determined by X-ray diffraction, and the extent of disorder continues to develop throughout the defectfluorite region. The Zr and Y L-edge spectra are very sensitive to changes in the local structure; such sensitivity enables us to reveal the progressive nature of the phase transition. Experimental results are supported by ab initio atomic scale simulations, which provide a mechanism for disorder to initiate in the pyrochlore structure. Further, the coordination numbers of the cations in both the defect-fluorite and pyrochlore structures are predicted, and the trends agree well with the experimental XANES results. The calculations predict that the coordination of cations in the Y2Zr2O7 defect-fluorite (normally considered to be 7 for all cations) varies depending on the species with the average coordination of Y and Zr being 7.2 and 6.8, respectively. © 2013, American Chemical Society.
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    An investigation of LnUO4 (Ln = Dy and Ho): structures, microstructures, uranium valences and magnetic properties
    (Elsevier, 2021-09-12) Lu, KT; Zhang, YJ; Wei, T; Zhang, ZM; Avdeev, M; Zheng, RK
    The phase formation, structures, microstructures, uranium valences and magnetic properties of LnUO4 (Ln = Dy and Ho) were investigated. Although sintering of the precursors in argon at 1450 °C for seven days and 1400 °C for six hours both resulted in the desired phase, sintering at higher temperature for longer duration led to the formations of well crystalized lanthanide monouranates with much better homogeneity. Cubic fluorite structures were determined using X-ray diffraction data, which was confirmed with transmission electron microscopy and Raman spectroscopy. The nature of pentavalent uranium was verified with a combination of diffuse reflectance and X-ray photoelectron spectroscopies. The magnetic suseptability measurements revealed that they are paramagnetic with no long-range magnetic orders, likely due to the extensive short-range oxygen defects. Overall the improved structural and spectroscopic understandings of LnUO4 have implications in nuclear materials especially for potential accident tolerance fuels and spent fuel management. Crown Copyright © 2021 Published by Elsevier Ltd.
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    Key role of Bismuth in the magnetoelastic transitions of Ba3BiIr2O9 and Ba3BiRu2O9 as revealed by chemical doping
    (America Chemical Society, 2013-12-24) Blanchard, PER; Huang, ZX; Kennedy, BJ; Liu, S; Miiller, W; Reynolds, EM; Zhou, QD; Avdeev, M; Zhang, ZM; Aitken, JB; Cowie, BCC; Jang, LY; Tan, TT; Li, S; Ling, CD
    The key role played by bismuth in an average intermediate oxidation state in the magnetoelastic spin-gap compounds Ba3BiRu2O9 and Ba3BiIr2O9 has been confirmed by systematically replacing bismuth with La3+ and Ce4+. Through a combination of powder diffraction (neutron and synchrotron), X-ray absorption spectroscopy, and magnetic properties measurements, we show that Ru/Ir cations in Ba3BiRu2O9 and Ba3BiIr2O9 have oxidation states between +4 and +4.5, suggesting that Bi cations exist in an unusual average oxidation state intermediate between the conventional +3 and +5 states (which is confirmed by the Bi L3-edge spectrum of Ba3BiRu2O9). Precise measurements of lattice parameters from synchrotron diffraction are consistent with the presence of intermediate oxidation state bismuth cations throughout the doping ranges. We find that relatively small amounts of doping (∼10 at%) on the bismuth site suppress and then completely eliminate the sharp structural and magnetic transitions observed in pure Ba3BiRu2O9 and Ba3BiIr2O9, strongly suggesting that the unstable electronic state of bismuth plays a critical role in the behavior of these materials. © 2013 American Chemical Society.
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    Lattice disorder and oxygen migration pathways in pyrochlore and defect-fluorite oxides
    (International Union of Crystallography, 2021-08-14) Marlton, FP; Zhang, ZM; Zhang, YP; Proffen, TE; Ling, CD; Kennedy, BJ
    Pyrochlore oxides, with the general formula A2B2O7, are of considerable interest as catalysts for the oxygen evolution reaction[1-5], where A2Ru2O7-δ pyrochlores have recently emerged as state-of-the-art materials, and as photocatalysts for hydrogen evolution[6-8]. Fundamental to their reactivity is the local-scale vacancy ordering and mobility, which can be tailored through cation substitution[4]. The chemical and structural flexibility of pyrochlore oxides gives them a diverse range of physical and chemical properties leading to technological applications including as fast-ion conductors[9, 10], ferroelectrics[11], magnetism[12], oxide heterostructures[13, 14], and host matrices for the immobilization of actinide-rich nuclear wastes[15]. Atomic-scale disorder plays an important role in the chemical and physical properties of oxide materials. The structural flexibility of pyrochlore-type oxides allows for crystal-chemical engineering of these properties. Compositional modification can push pyrochlore oxides towards a disordered defect-fluorite structure with anion Frenkel pair defects that facilitate oxygen migration. The local structure of the long-range average cubic defect-fluorite was recently claimed to consist of randomly arranged orthorhombic weberitetype domains[16]. In this work we show, using low-temperature neutron total-scattering experiments, that this is not the case for Zrrich defect-fluorites. By analyzing data from the pyrochlore/defect-fluorite Y2Sn2-xZrxO7 series using a combination of neutron pair distribution function and big-box modelling, we have differentiated and quantified the relationship between anion sub-lattice disorder and Frenkel defects. These details directly influence the energy landscape for oxygen migration and are crucial for simulations and design of new materials with improved properties. © The Authors
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    Novel chemical synthesis and characterization of CeTi2O6 brannerite
    (ACS Publications, 2014-06-13) Kong, L; Gregg, DJ; Karatchevtseva, I; Zhang, ZM; Blackford, MG; Middleburgh, SC; Lumpkin, GR; Triani, G
    Cerium titanate CeTi2O6 was prepared by a new soft chemistry route in aqueous solution. A suite of characterization techniques, including X-ray diffraction, thermal analysis, vibrational spectroscopy, and scanning and transmission electron spectroscopy, were employed to investigate the brannerite structure formation and its bulk properties. The synthesized powder formed the brannerite crystal structure upon calcination at temperatures as low as 800 °C. Samples sintered at 1350 °C possess a high level of crystallinity. X-ray absorption near-edge structure results indicate the presence of six-coordinated Ce4+ in the brannerite samples. © 2014, American Chemical Society.
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    Peroxide defect formation in zirconate perovskites
    (Royal Society of Chemistry, 2014) Middleburgh, SC; Karatchevtseva, I; Kennedy, BJ; Burr, PA; Zhang, ZM; Reynolds, EM; Grimes, RW; Lumpkin, GR
    Atomic scale modelling suggests that excess oxygen can be accommodated in the group II perovskite zirconates by the formation of peroxide ion defects. This is unprecedented given the lack of charge compensating defects required for standard excess oxygen accommodation. The solution energy of O2 was predicted to be close to zero for BaZrO3, accommodating the peroxide ion defect more easily than in SrZrO3 or CaZrO3. This was experimentally examined by exposing SrZrO3 and BaZrO3 to hydrogen peroxide solution and then carrying out Raman spectroscopy measurements to look for a peak indicative of peroxide ions. A peak was observed at ∼1000 cm−1 in both compositions, suggesting the theoretically predicted peroxide ion is present. © 2014, The Royal Society of Chemistry.
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    Physical stability and durability of heavy-ion irradiated crystalline zirconolite CaZrTh2O7 ceramic designed for minor actinide disposition
    (Commissariat à l'énergie atomique (CEA), 2004-07-01) Advocat, T; McGlinn, PJ; Smith, KL; Gosset, D; Rabiller, H; Zhang, ZM; Lumpkin, GR; Chaumont, J
    External irradiation studies with heavy ions Pb3+ accelerated at 510 keV were conducted on non radioactive zirconolite ceramic pellets, containing actinide surrogates such as Rare Earth Elements (REE). Ion irradiation of ceramic pellet surfaces has transformed the outermost several tenths of nanometers of the surface into a metamict state. The chemical durability in water of the irradiated zirconolite ceramics was measured at 100 deg C. The dissolution behavior is similar to that for the fully crystalline materials, and natural zirconolite minerals as well, which are at least several hundred million years old and self-irradiated up to 10 20}alpha decay/g due to the presence of appreciable quantities of Th and U. The amorphization process of the crystalline structure by the alpha decay does not modify the high chemical durability of zirconolite.
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    Probing long- and short-range disorder in Y2Ti2–xHfxO7 by diffraction and spectroscopy techniques
    (American Chemical Society, 2016-11-01) Zhang, ZM; Avdeev, M; de los Reyes, M; Lumpkin, GR; Kennedy, BJ; Blanchard, PER; Liu, S; Tadich, A; Cowie, BCC
    We studied the long-range average and short-range local structures in Y2Ti2–xHfxO7 (x = 0–2.0) using diffraction and spectroscopy techniques, respectively. Both neutron and synchrotron X-ray powder diffraction data show a clear phase transition of the average structure from ordered pyrochlore to disordered defect-fluorite at x ≈ 1.6; the long-range anion disorder appears to develop gradually throughout the entire pyrochlore region in contrast to the rapid loss of cation ordering from x = 1.4 to 1.6. The commonly observed two-phase region around the pyrochlore/defect-fluorite phase boundary is absent in this system, demonstrating high sample quality. X-ray absorption near-edge structure (XANES) results at the Y L2-, Ti K- and L3,2-, Hf L3-, and O K-edges indicate a gradual local structural evolution across the whole compositional range; the Y coordination number (CN) decreases and the CN around Ti and Hf increases with increasing Hf content (x). The spectroscopic results suggest that the local disorder occurs long before the pyrochlore to defect-fluorite phase boundary as determined by diffraction, and this disorder evolves continuously from short- to medium- and eventually to long-range detectable by diffraction. This study highlights the complex disordering process in pyrochlore oxides and the importance of a multitechnique approach to tackle disorder over different length scales and in the anion and cation sublattices, respectively. The results are important in the context of potential applications of these oxides such as ionic conductors and radiation-resistant nuclear waste forms. © 2016 American Chemical Society
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    Pyrochlore based glass-ceramics for the immobilization of actinide-rich nuclear wastes: from concept to reality
    (Elsevier, 2013-01-01) Zhang, YJ; Zhang, ZM; Thorogood, GJ; Vance, ER
    Pyrochlore based glass-ceramics have been developed, from concept to reality, for the immobilization of actinide-rich nuclear wastes. Compared with zirconolite based glass-ceramics, they are less sensitive to the processing redox conditions and can double actinide waste loadings thus decreasing volumes of the consolidated waste forms, and subsequently reducing the interim storage and disposal costs. More importantly, they provide an alternative flexible system to tackle radioactive wastes arising from the advanced nuclear reactors. © 2012, Elsevier B.V.
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    Pyrochlore glass‐ceramics fabricated via both sintering and hot isostatic pressing for minor actinide immobilization
    (John Wiley & Sons, Inc., 2020-03-19) Zhang, YJ; Zhang, ZM; Wei, T; Kong, L; Kim, YJ; Gregg, DJ
    Pyrochlore glass‐ceramics (GCs) have been investigated with samples fabricated via both sintering and hot isostatic pressing (HIPing) of a mixed oxide precursor. It has been demonstrated that sintering at 1200°C in air is necessary to obtain well‐crystallized pyrochlore crystals in a sodium aluminoborosilicate glass through a one‐step controlled cooling. The crystallization, structure, and microstructure of Eu2Ti2O7 pyrochlore as the major phases in residual glass were confirmed with X‐ray diffraction (XRD), scanning electron microscopy‐energy dispersive spectroscopy, transmission electron microscopy, and Raman spectroscopy. The structures of major Eu2Ti2O7 pyrochlore and minor [Eu4.67O(SiO4)3] apatite in both sintered and HIPed samples were refined using synchrotron XRD data. While the processing atmosphere did not appear to affect the cell parameter of the main pyrochlore phase, very small volume expansion (~0.3%) was observed for the minor apatite phase in the HIPed sample. In addition, static leaching of the HIPed sample confirmed that pyrochlore GCs are chemically durable. Overall, pyrochlore GCs prepared via both sintering and HIPing with the Eu partitioning factor of ~23 between ceramics and the residual glass are suitable waste forms for minor actinides with processing chemicals. © 1999-2020 John Wiley & Sons, Inc.