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A W Sleight - One of the best experts on this subject based on the ideXlab platform.
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bulk Thermal Expansion for tungstate and molybdates of the type a2m3o12
Journal of Materials Research, 1999Co-Authors: T A Mary, A W SleightAbstract:Bulk Thermal Expansion properties of 19 members of the A 2 M 3 O 12 family of tungstates and molybdates were determined from room temperature to 800 °C. The observed behavior ranges from strong negative Thermal Expansion (α = −11 × 10 −6 K −1 ) in Sc 2 W 3 O 12 to near zero Thermal Expansion in Al 1.68 Sc 0.02 In 0.30 W 3 O 12 .
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enhanced negative Thermal Expansion in lu2w3o12
Journal of Solid State Chemistry, 1998Co-Authors: P M Forster, A Yokochi, A W SleightAbstract:Abstract Negative Thermal Expansion in the Sc 2 W 3 O 12 family has been pushed to much more pronounced values by substituting a large cation for Sc. X-ray diffraction measurements from 127 to 627°C give a linear Thermal Expansion coefficient of −6.8×10 −6 /°C for Lu 2 W 3 O 12 compared to −2.2×10 −6 /°C for Sc 2 W 3 O 12 . Negative Thermal Expansion in this family is dependent on the rocking motions of polyhedra. However, polyhedra in this structure cannot rock without changing their shape. Larger cations expand the octahedra, reducing the oxygen–oxygen repulsions within the polyhedra. This facilitates the polyhedra shape changes necessary for the rocking motions required for negative Thermal Expansion.
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isotropic negative Thermal Expansion
Annual Review of Materials Science, 1998Co-Authors: A W SleightAbstract:▪ Abstract Materials that contract on heating are unusual and have important applications. Materials showing such negative Thermal Expansion behavior are usually anisotropic and usually exhibit this behavior over only a small temperature range. The zirconium tungstate family is unique in showing strong negative Thermal Expansion over a broad temperature range.
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negative Thermal Expansion in sc2 wo4 3
Journal of Solid State Chemistry, 1998Co-Authors: John S O Evans, T A Mary, A W SleightAbstract:Abstract Sc2(WO4)3has been found to show the highly unusual property of negative Thermal Expansion over a temperature range of 10 to 1073 K. Powder neutron diffraction data from 10 to 450 K shows an essentially linear decrease in cell volume as a function of temperature. The intrinsic linear coefficient of Thermal Expansion from this data is −2.2×10−6K−1. The linear coefficient of Thermal Expansion measured on a ceramic bar of Sc2(WO4)3can be as negative as −11×10−6K−1due to microstructure changes as a function of temperature. Rietveld refinement as a function of temperature suggests that the intrinsic negative Thermal Expansion can be related to transverse vibrations of bridging oxygen atoms in the structure. The anharmonic nature of these vibrations leads to a coupled tilting of the quasi-rigid framework polyhedra. This tilting in turn causes the structure to become more dense with increasing temperature.
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negative Thermal Expansion materials
Physica B-condensed Matter, 1997Co-Authors: John S O Evans, T A Mary, A W SleightAbstract:Abstract The recent discovery of negative Thermal Expansion over an unprecedented temperature range in ZrW 2 O 8 (which contracts continuously on warming from below 2 K to above 1000 K) has stimulated considerable interest in this unusual phenomenon. Negative and low Thermal Expansion materials have a number of important potential uses in ceramic, optical and electronic applications. We have now found negative Thermal Expansion in a large new family of materials with the general formula A 2 (MO 4 ) 3 . Chemical substitution dramatically influences the Thermal Expansion properties of these materials allowing the production of ceramics with negative, positive or zero coefficients of Thermal Expansion, with the potential to control other important materials properties such as refractive index and dielectric constant. The mechanism of negative Thermal Expansion and the phase transitions exhibited by this important new class of low-Expansion materials will be discussed.
Koshi Takenaka - One of the best experts on this subject based on the ideXlab platform.
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progress of research in negative Thermal Expansion materials paradigm shift in the control of Thermal Expansion
Frontiers in Chemistry, 2018Co-Authors: Koshi TakenakaAbstract:To meet strong demands for the control of Thermal Expansion necessary because of the advanced development of industrial technology, widely various giant negative Thermal Expansion (NTE) materials have been developed during the last decade. Discovery of large isotropic NTE in ZrW2O8 has greatly advanced research on NTE deriving from its characteristic crystal structure, which is now classified as conventional NTE. Materials classified in this category have increased rapidly. In addition to development of conventional NTE materials, remarkable progress has been made in phase-transition-type NTE materials using a phase transition accompanied by volume contraction upon heating. These giant NTE materials have brought a paradigm shift in the control of Thermal Expansion. This report classifies and reviews mechanisms and materials of NTE to suggest means of improving their functionality and of developing new materials. A subsequent summary presents some recent activities related to how these giant NTE materials are used as practical Thermal Expansion compensators, with some examples of composites containing these NTE materials.
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colossal negative Thermal Expansion in reduced layered ruthenate
Nature Communications, 2017Co-Authors: Koshi Takenaka, Yoshihiko Okamoto, Tsubasa Shinoda, Naoyuki Katayama, Yuki SakaiAbstract:Large negative Thermal Expansion (NTE) has been discovered during the last decade in materials of various kinds, particularly materials associated with a magnetic, ferroelectric or charge-transfer phase transition. Such NTE materials have attracted considerable attention for use as Thermal-Expansion compensators. Here, we report the discovery of giant NTE for reduced layered ruthenate. The total volume change related to NTE reaches 6.7% in dilatometry, a value twice as large as the largest volume change reported to date. We observed a giant negative coefficient of linear Thermal Expansion α=-115 × 10-6 K-1 over 200 K interval below 345 K. This dilatometric NTE is too large to be attributable to the crystallographic unit-cell volume variation with temperature. The highly anisotropic Thermal Expansion of the crystal grains might underlie giant bulk NTE via microstructural effects consuming open spaces in the sintered body on heating.
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tailoring Thermal Expansion in metal matrix composites blended by antiperovskite manganese nitrides exhibiting giant negative Thermal Expansion
Journal of Applied Physics, 2012Co-Authors: Koshi Takenaka, T Hamada, D Kasugai, Norihiro SugimotoAbstract:We controlled Thermal Expansion of metal matrix composites (MMCs) that had been blended using antiperovskite manganese nitrides with giant negative Thermal Expansion (NTE). The NTE of the manganese nitrides, which is isotopic, is greater than −30 ppm K−1 in α (coefficient of linear Thermal Expansion), which is several or ten times as large as that of conventional NTE materials. These advantages of nitrides are desirable for practical application as a Thermal-Expansion compensator, which can suppress Thermal Expansion of various materials including metals and even plastics. Powder metallurgy using pulsed electric current sintering enables us to reduce temperatures and times for fabrication of MMCs. Consequently, chemical reactions between matrix (Al, Ti, Cu) and filler can be controlled and even high-melting-point metals can be used as a matrix. Thermal Expansion of these MMCs is tunable across widely various α values, even negative ones, with high reproducibility. These composites retain a certain amount ...
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Negative Thermal Expansion materials: Technological key for control of Thermal Expansion
Science and Technology of Advanced Materials, 2012Co-Authors: Koshi TakenakaAbstract:Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative Thermal Expansion (NTE) materials have enormous industrial merit because they can control the Thermal Expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear Thermal Expansion over −30 ppmK−1. Such giant NTE is opening a new phase of control of Thermal Expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade.
Kengo Oka - One of the best experts on this subject based on the ideXlab platform.
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negative Thermal Expansion induced by intermetallic charge transfer
Science and Technology of Advanced Materials, 2015Co-Authors: Masaki Azuma, Kengo Oka, Koichiro NabetaniAbstract:Suppression of Thermal Expansion is of great importance for industry. Negative Thermal Expansion (NTE) materials which shrink on heating and expand on cooling are therefore attracting keen attention. Here we provide a brief overview of NTE induced by intermetallic charge transfer in A-site ordered double perovskites SaCu3Fe4O12 and LaCu3Fe4-x Mn x O12, as well as in Bi or Ni substituted BiNiO3. The last compound shows a colossal dilatometric linear Thermal Expansion coefficient exceeding -70 × 10-6 K-1 near room temperature, in the temperature range which can be controlled by substitution.
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suppression of temperature hysteresis in negative Thermal Expansion compound bini1 xfexo3 and zero Thermal Expansion composite
Applied Physics Letters, 2015Co-Authors: Koichiro Nabetani, Kengo Oka, Masaichiro Mizumaki, Y Muramatsu, Kiho Nakano, Hajime Hojo, Akane Agui, Yuji Higo, Naoto HayashiAbstract:Negative Thermal Expansion (NTE) of BiNi1−xFexO3 is investigated. All x = 0.05, 0.075, 0.10, and 0.15 samples shows large NTE with the coefficient of linear Thermal Expansion (CTE) αL exceeding −150 ppm K−1 induced by charge transfer between Bi5+ and Ni2+ in the controlled temperature range near room temperature. Compared with Bi1−xLnxNiO3 (Ln: rare-earth elements), the Thermal hysteresis that causes a problem for practical application is suppressed because random distribution of Fe in the Ni site changes the first order transition to second order-like transition. The CTE of BiNi0.85Fe0.15O3 reaches −187 ppm K−1 and it is demonstrated that 18 vol. % addition of the present compound compensates for the Thermal Expansion of epoxy resin.
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colossal negative Thermal Expansion in binio3 induced by intermetallic charge transfer
Nature Communications, 2011Co-Authors: Weitin Chen, Masaki Azuma, Hayato Seki, Michal Czapski, Smirnova Olga, Kengo Oka, Masaichiro MizumakiAbstract:The unusual property of negative Thermal Expansion is of fundamental interest and may be used to fabricate composites with zero or other controlled Thermal Expansion values. Here we report that colossal negative Thermal Expansion (defined as linear Expansion <-10(-4) K(-1) over a temperature range ~100 K) is accessible in perovskite oxides showing charge-transfer transitions. BiNiO(3) shows a 2.6% volume reduction under pressure due to a Bi/Ni charge transfer that is shifted to ambient pressure through lanthanum substitution for Bi. Changing proportions of coexisting low- and high-temperature phases leads to smooth volume shrinkage on heating. The crystallographic linear Expansion coefficient for Bi(0.95)La(0.05)NiO(3) is -137×10(-6) K(-1) and a value of -82×10(-6) K(-1) is observed between 320 and 380 K from a dilatometric measurement on a ceramic pellet. Colossal negative Thermal Expansion materials operating at ambient conditions may also be accessible through metal-insulator transitions driven by other phenomena such as ferroelectric orders.
Masaki Azuma - One of the best experts on this subject based on the ideXlab platform.
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negative Thermal Expansion induced by intermetallic charge transfer
Science and Technology of Advanced Materials, 2015Co-Authors: Masaki Azuma, Kengo Oka, Koichiro NabetaniAbstract:Suppression of Thermal Expansion is of great importance for industry. Negative Thermal Expansion (NTE) materials which shrink on heating and expand on cooling are therefore attracting keen attention. Here we provide a brief overview of NTE induced by intermetallic charge transfer in A-site ordered double perovskites SaCu3Fe4O12 and LaCu3Fe4-x Mn x O12, as well as in Bi or Ni substituted BiNiO3. The last compound shows a colossal dilatometric linear Thermal Expansion coefficient exceeding -70 × 10-6 K-1 near room temperature, in the temperature range which can be controlled by substitution.
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colossal negative Thermal Expansion in binio3 induced by intermetallic charge transfer
Nature Communications, 2011Co-Authors: Weitin Chen, Masaki Azuma, Hayato Seki, Michal Czapski, Smirnova Olga, Kengo Oka, Masaichiro MizumakiAbstract:The unusual property of negative Thermal Expansion is of fundamental interest and may be used to fabricate composites with zero or other controlled Thermal Expansion values. Here we report that colossal negative Thermal Expansion (defined as linear Expansion <-10(-4) K(-1) over a temperature range ~100 K) is accessible in perovskite oxides showing charge-transfer transitions. BiNiO(3) shows a 2.6% volume reduction under pressure due to a Bi/Ni charge transfer that is shifted to ambient pressure through lanthanum substitution for Bi. Changing proportions of coexisting low- and high-temperature phases leads to smooth volume shrinkage on heating. The crystallographic linear Expansion coefficient for Bi(0.95)La(0.05)NiO(3) is -137×10(-6) K(-1) and a value of -82×10(-6) K(-1) is observed between 320 and 380 K from a dilatometric measurement on a ceramic pellet. Colossal negative Thermal Expansion materials operating at ambient conditions may also be accessible through metal-insulator transitions driven by other phenomena such as ferroelectric orders.
Xianran Xing - One of the best experts on this subject based on the ideXlab platform.
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intrinsic volumetric negative Thermal Expansion in the rigid calcium squarate
Chemical Communications, 2021Co-Authors: Zhanning Liu, Zhe Wang, Daofeng Sun, Xianran XingAbstract:The calcium squarate with a rigid framework is found to exhibit volumetric negative Thermal Expansion (NTE) with the coefficient −9.51(5) × 10−6 K−1 and uniaxial zero Thermal Expansion (ZTE, −0.14(4) × 10−6 K−1) over a wide temperature. Detailed comparison of the long–range and local structure sheds light on the fact that the anomalous Thermal Expansion originates from the transverse vibration of the bridging squarate ligand, although it has been tightly bonded by five calcium ions. We believe that this study can provide a deep insight into the origin of NTE and the structural flexibility of metal organic frameworks (MOFs).
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argentophilicity induced anomalous Thermal Expansion behavior in a 2d silver squarate
Inorganic chemistry frontiers, 2021Co-Authors: Zhanning Liu, Xianran Xing, Jianjian Yang, Lilong Yang, Rongming Wang, Daofeng SunAbstract:Over the past decades, two dimensional (2D)-structured materials have attracted considerable interest due to not only their intrinsic aesthetic appeal but also their intriguing physical properties. Herein, a 2D bilayer silver squarate was synthesized, which showed combined colossal positive Thermal Expansion (PTE) along the packing direction and negative Thermal Expansion (NTE) within the layer. The combined analyses of high resolution synchrotron X-ray powder diffraction, atomic pair distribution function (PDF) and Raman spectra shed light on the anomalous Thermal Expansion behaviors being closely related to the interlayer argentophilicity and Thermal flipping of the ligand. Furthermore, this compound exhibited an intrinsic moderate proton conductivity (1.2 × 10−4 S cm−1 at 80 °C under 98% RH). We believe that this work can not only deepen our understanding of the Thermal Expansion properties of 2D materials but also provide guidance for the design and synthesis of novel functional materials.
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magnetic field induced strong negative Thermal Expansion in la fe al 13
Chemistry of Materials, 2020Co-Authors: Yuzhu Song, Qingzhen Huang, Rongjin Huang, Yun Liu, Zhenhuan Zhang, Yong Jiang, Shouguo Wang, Xianran XingAbstract:Negative Thermal Expansion (NTE) plays an increasingly important role in the control of Thermal Expansion of materials. However, the discovery of strong NTE materials, which is rare, remains challe...
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negative Thermal Expansion in molecular materials
Chemical Communications, 2018Co-Authors: Zhanning Liu, Jun Chen, Jinxia Deng, Kun Lin, Qilong Gao, Xianran XingAbstract:Negative Thermal Expansion (NTE), whereby lattices contract upon heating, is of considerable interest for its wide applications in many fields. Molecular materials have been widely investigated as catalysts, sensors, etc., which usually endure temperature vibration. NTE can become a substantial means for controlling the coefficients of Thermal Expansion. Molecular materials possess plentiful structures and can be easily decorated, making them ideal platforms for Thermal Expansion modification. In this feature article, we provide an overview of the recent developments in utilizing NTE in molecular materials and summarize some mechanisms leading to NTE. The discussion of NTE in molecular materials concerns many factors, including transverse vibration, geometric flexibility, host-guest interactions, spin crossover, molecular packing rearrangement and molecular conformational changes.
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phase transition and negative Thermal Expansion in orthorhombic dy2w3o12
RSC Advances, 2016Co-Authors: Weigang Cao, Jun Chen, Jinxia Deng, Kun Lin, Zhanning Liu, Xianran XingAbstract:New materials with suitable negative Thermal Expansion (NTE) are much desired to control Thermal Expansion in solids. In the present study, we determined the phase transition temperature of Dy2W3O12 from the monoclinic phase to the orthorhombic phase at 996 °C. The orthorhombic phase could be retained by quenching, and further high temperature XRD and synchrotron radiation X-ray powder diffraction (SXRD) experiments revealed that Dy2W3O12 shows NTE (−2.6 × 10−5 °C−1) in the temperature range of 150–500 °C, which is the largest negative Thermal Expansion in the A2W3O12 family (A = rare earth element). A possible NTE mechanism and enhanced NTE were elucidated by the transverse Thermal motion of the bridge oxygen in A–O–W linkages accompanied by distortion of the polyhedra with large Dy3+ on the A site.
