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1.
High‐pressure behavior of (Cs,K)Al4Be5B11O28 (londonite): A single‐crystal synchrotron diffraction study up to 26 GPa
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Giacomo Diego Gatta Paolo Lotti Davide Comboni Marco Merlini Pietro Vignola Hanns‐Peter Liermann 《Journal of the American Ceramic Society》2017,100(10):4893-4901
The compressional behavior and the P‐induced deformation mechanisms at the atomic scale of (Cs,K)Al4Be5B11O28 (londonite, a ~7.31 Å and space group P3m) were investigated by in situ single‐crystal synchrotron X‐ray diffraction with a diamond anvil cell up to 26 GPa. No phase transition was observed within the P‐range investigated: this material exhibits isotropic compression (i.e., with cubic symmetry) in response to the applied pressure. Fitting the P–V data with a Birch‐Murnaghan isothermal equation of state, we obtained: V0=390.8(3) Å3, KP0=212(7) GPa (β0=1/KP0=0.0047(1) GPa?1) and K′=4.6(6). A series of structural refinements, based on the high‐pressure intensity data, were performed. The stiffness of londonite (similar to that of carbides) is governed by its close‐packing structure, and in particular by the very low compressibility of B‐ and Be‐tetrahedra and the modest compressibility of the Al‐octahedra. The Cs‐polyhedra are the most compressible units of the structure. The effects of pressure can be accommodated by intrapolyhedral compression or deformation, leading to a modest bulk compression. The high amount of boron in londonite (B2O3 ~50 wt%) makes its synthetic counterpart a potential neutron absorber. In addition, the high content of Cs makes londonite‐type materials as potential hosts for nuclear waste. 相似文献
2.
Qianhong Yi Dehui Liang Qing Ma Ming Huang Bisheng Tan Yucun Liu Yu Chi 《Propellants, Explosives, Pyrotechnics》2016,41(5):906-911
The energetic material 3‐(4‐aminofurazan‐3‐yl)‐4‐(4‐nitrofurazan‐3‐yl)furazan (ANTF) with low melting‐point was synthesized by means of an improved oxidation reaction from 3,4‐bis(4′‐aminofurazano‐3′‐yl)furazan. The structure of ANTF was confirmed by 13C NMR spectroscopy, mass spectrometry, and the crystal structure was determined by X‐ray diffraction. ANTF crystallized in monoclinic system P21/c, with a crystal density of 1.785 g cm−3 and crystal parameters a=6.6226(9) Å, b=26.294(2) Å, c=6.5394(8) Å, β=119.545(17)°, V=0.9907(2) nm3, Z=4, μ=0.157 mm−1, F(000)=536. The thermal stability and non‐isothermal kinetics of ANTF were studied by differential scanning calorimetry (DSC) with heating rates of 2.5, 5, 10, and 20 K min−1. The apparent activation energy (Ea) of ANTF calculated by Kissinger's equation and Ozawa's equation were 115.9 kJ mol−1 and 112.6 kJ mol−1, respectively, with the pre‐exponential factor lnA=21.7 s−1. ANTF is a potential candidate for the melt‐cast explosive with good thermal stability and detonation performance. 相似文献
3.
Yinglei Wang Kangzhen Xu Fengqi Zhao Yueping Ji Jianhua Yi Siyu Xu Fulei Gao Bin Chen 《Propellants, Explosives, Pyrotechnics》2013,38(5):644-650
The energetic material, 3‐nitro‐1,5‐bis(4,4′‐dimethyl azide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP), was firstly synthesized by means of Click Chemistry using 1,5‐diazido‐3‐nitrazapentane as main material. The structure of NDTAP was confirmed by IR, 1H NMR, and 13C NMR spectroscopy; mass spectrometry, and elemental analysis. The crystal structure of NDTAP was determined by X‐ray diffraction. It belongs to monoclinic system, space group C2/c with crystal parameters a=1.7285(8) nm, b=0.6061(3) nm, c=1.6712(8) nm, β=104.846(8)°, V=1.6924(13) nm3, Z=8, μ=0.109 mm−1, F(000)=752, and Dc=1.422 g cm−3. The thermal behavior and non‐isothermal decomposition kinetics of NDTAP were studied with DSC and TG‐DTG methods. The self‐accelerating decomposition temperature and critical temperature of thermal explosion are 195.5 and 208.2 °C, respectively. NDTAP presents good thermal stability and is insensitive. 相似文献
4.
Margaret‐Jane Crawford Jürgen Evers Michael Gbel ThomasM. Klaptke Peter Mayer Gilbert Oehlinger JanM. Welch 《Propellants, Explosives, Pyrotechnics》2007,32(6):478-495
1,1‐Diamino‐2,2‐dinitroethene, C2H4N4O4 (FOX‐7), is a novel high energy density material with low friction and impact sensitivity and a high activation barrier to detonation. In this study, the previously unknown crystal structure of the γ‐polymorph of trimorphic FOX‐7 is reported. γ‐FOX‐7 is stable from ∼435 K until the compound decomposes just above 504 K. A single crystal of α‐FOX‐7 (P21/n, Z=4, a=694.67(7) pm, b=668.87(9) pm, c=1135.1(1) pm, β=90.14(1)°, T=373 K) was first transformed into a single crystal of β‐FOX‐7 (P212121, Z=4, a=698.6(1) pm, b=668.6(2) pm, c=1168.7(3) pm, T=423 K) and then into a single crystal of γ‐FOX‐7 at 450 K. The γ‐FOX‐7 crystal was then subsequently quenched to 200 K. The structure of γ‐FOX‐7 (P21/n, Z=8, a=1335.4(3) pm, b=689.5(1) pm, c=1205.0(2) pm, β=111.102(8)°, T=200 K) consists of four planar layers, each containing two crystallographically independent FOX‐7 molecules found in the asymmetric unit. 相似文献
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Davide Comboni Francesco Pagliaro G. Diego Gatta Paolo Lotti Sula Milani Marco Merlini Tommaso Battiston Konstantin Glazyrin Hanns-Peter Liermann 《Journal of the American Ceramic Society》2020,103(9):5291-5301
The high-pressure behavior of kernite [ideally Na2B4O6(OH)2·3H2O, a ~ 7.02 Å, b ~ 9.16 Å, c ~ 15.68 Å, β = 108.9°, Sp Gr P21/c, at ambient conditions], an important B-bearing raw material (with B2O3 ≈ 51 wt%) and a potential B-rich aggregate in radiation shielding materials, has been studied by single-crystal synchrotron X-ray diffraction up to 14.6 GPa. Kernite undergoes an iso-symmetric phase transition at 1.6-2.0 GPa (to kernite-II). Between 6.6-7.5 GPa, kernite undergoes a second phase transition, possibly iso-symmetric in character (to kernite-III). The crystal structure of kernite-II was solved and refined. The isothermal bulk modulus (KV0 = β-1P0,T0, where βP0,T0 is the volume compressibility coefficient) of the ambient-pressure polymorph of kernite was found to be KV0 = 29(1) GPa and a marked anisotropic compressional pattern, with K(a)0: K(b)0: K(c)0~1:3:1.5., was observed. In kernite-II, the KV0 increases to 43.3(9) GPa and the anisotropic compressional pattern increases pronouncedly. The mechanisms, at the atomic scale, which govern the structure deformation, have been described. 相似文献
7.
Chaza Darwich ThomasM. Klaptke JanM. Welch Muhamed Suceska 《Propellants, Explosives, Pyrotechnics》2007,32(3):235-243
3,4,5‐Triamino‐1,2,4‐triazolium 5‐nitrotetrazolate ( 2 ) was synthesized in high yield from 3,4,5‐triamino‐1,2,4‐triazole (guanazine) ( 1 ) and ammonium 5‐nitrotetrazolate. The new compound 2 was characterized by vibrational (IR and Raman) and multinuclear NMR spectroscopy (1H, 13C, 15N), elemental analysis and single crystal X‐ray diffraction (triclinic, P(‐1), a=0.7194(5), b=0.8215(5), c=0.8668(5) nm, α=75.307(5), β=70.054(5), γ=68.104(5)°, V=0.4421(5) nm3, Z=2, ϱ=1.722 g cm−1, R1=0.0519 [F>4σ(F)], wR2(all data)=0.1154). The 15N NMR spectrum and X‐ray crystal structure (triclinic, P‐1, a=0.5578(5), b=0.6166(5), c=0.7395(5) nm, α=114.485(5)°, β=90.810(5)°, γ=97.846(5)°, V=0.2286(3) nm3, Z=2, ϱ=1.658 g cm−1, R1=0.0460 [F>4σ(F)], wR2(all data)=0.1153) of 1 were also determined. 相似文献
8.
DMSO/water (80/20 volume ratio) solutions of commercial poly(vinyl alcohol)s (a‐PVA99, a‐PVA88) with degrees of saponification of 99.3 and 88 mol % were gel‐spun into methanol (−20 and −70°C). The dry filaments obtained were drawn at 200°C (a‐PVA99) and 150–180°C (a‐PVA88). The maximum draw ratio and Young's modulus were 26 and 34 GPa for a‐PVA99 and 21 and 24 GPa for a‐PVA88 (drawing temperature: 160°C). So, at first, the dry filaments obtained for a‐PVA88 were drawn at 150–180°C until 10 times their original length. Moreover, the predrawn a‐PVA88 filaments were perfectly saponificated under fixing at the both ends and then the filaments were redrawn at 200°C. The maximum draw ratio and Young's modulus for the filaments (a‐PVA88→99) predrawn at 150°C were 28 and 39 GPa, respectively. The a‐PVA88→99 filaments had two melting peaks (228 and 236°C). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2872–2876, 2000 相似文献
9.
Kimberly J. Miller Carl P. Romao Mario Bieringer Bojan A. Marinkovic Luciana Prisco Mary Anne White 《Journal of the American Ceramic Society》2013,96(2):561-566
In(HfMg)0.5Mo3O12, which can be considered as a 1:1 mole ratio solid solution of the low‐positive thermal expansion material HfMgMo3O12 and the low‐negative thermal expansion (NTE) material In2Mo3O12 was prepared. From DSC and XRPD results, we show that In(HfMg)0.5Mo3O12 exists in a monoclinic (P21/a) structure at low temperature and undergoes a phase transition at ~425 K to an orthorhombic phase (Pnma), with an associated enthalpy change of 0.89 kJ mol?1. Thermal expansion is large and positive in the low‐temperature monoclinic phase (average α? = 16 × 10?6 K?1 and 20 × 10?6 K?1, from dilatometry and XRPD, respectively). Remarkably, this material has a near‐zero thermal expansion (ZTE) coefficient over the temperature range ~500 to ~900 K in the high‐temperature orthorhombic phase, both intrinsically and for the bulk sample. The average linear intrinsic (XRPD) value is α? = ?0.4 × 10?6 K?1, and the average bulk (dilatometric) value is α? = 0.4 × 10?6 K?1 with an uncertainty of ± 0.2 × 10?6 K?1. The slight difference between intrinsic and bulk thermal expansion is attributed to microstructural effects. XRPD results show that the thermal expansion is more isotropic than for the parent compounds HfMgMo3O12 and In2Mo3O12. 相似文献
10.
Zhang Tonglai Lu Chunhua Zhang Jianguo Yu Kaibei 《Propellants, Explosives, Pyrotechnics》2003,28(5):271-276
The title compound {[Ca(CHZ)2(H2O)](NTO)2⋅3.5H2O}n was synthesized by using an aqueous solution of calcium 3‐nitro‐1,2,4‐triazol‐5‐onate and carbohydrazide (CHZ, NH2NHCONHNH2). Its molecular structure was determined by X‐ray diffraction and its crystals have monoclinic form, with space group C2/c, where a=2.4483(4) nm, b=1.2581(2) nm, c =1.6269(3) nm, β=121.168(12)°, V=4.2879(13) nm3, Z=8, dc=1.727 g⋅cm−3, μ (Mo Kα)=3.9 cm−1, M=557.47, F(000)=2312. The coordination polyhedron is a tricapped trigonal prism in a tetradecahedron with a coordination number of nine. The whole molecule has many long chains formed through the carbohydrazide bridges, and every long chain is unlimited along the c axis. The long chains are linked by hydrogen bonds to form the crystal structure. 相似文献
11.
David Adam Konstantin Karaghiosoff ThomasM. Klaptke Gerhard Holl Manfred Kaiser 《Propellants, Explosives, Pyrotechnics》2002,27(1):7-11
Triazidotrinitro benzene, 1,3,5‐(N3)3‐2,4,6‐(NO2)3C6 ( 1 ) was synthesized by nitration of triazidodinitro benzene, 1,3,5‐(N3)3‐2,4‐(NO2)2C6H with either a mixture of fuming nitric and concentrated sulfuric acid (HNO3/H2SO4) or with N2O5. Crystals were obtained by the slow evaporation of an acetone/acetic acid mixture at room temperature over a period of 2 weeks and characterized by single crystal X‐ray diffraction: monoclinic, P 21/c (no. 14), a=0.54256(4), b=1.8552(1), c=1.2129(1) nm, β=94.91(1)°, V=1.2163(2) nm3, Z=4, ϱ=1.836 g⋅cm−3, Rall =0.069. Triazidotrinitro benzene has a remarkably high density (1.84 g⋅cm−3). The standard heat of formation of compound 1 was computed at B3LYP/6‐31G(d, p) level of theory to be ΔH°f=765.8 kJ⋅mol−1 which translates to 2278.0 kJ⋅kg−1. The expected detonation properties of compound 1 were calculated using the semi‐empirical equations suggested by Kamlet and Jacobs: detonation pressure, P=18.4 GPa and detonation velocity, D=8100 m⋅s−1. 相似文献
12.
Synthesis of Al2O3/SiO2 nano‐nano composite ceramics under high pressure and its inverse Hall–Petch behavior
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Nico A. Gaida Norimasa Nishiyama Atsunobu Masuno Astrid Holzheid Hiroaki Ohfuji Ulrich Schürmann Christin Szillus Eleonora Kulik Jozef Bednarcik Oliver Beermann Christopher Giehl Lorenz Kienle 《Journal of the American Ceramic Society》2017,100(1):323-332
We report the synthesis of alumina/stishovite nano‐nano composite ceramics through a pressure‐induced dissociation in Al2SiO5 at a pressure of 15.6 GPa and temperatures of 1300°C‐1900°C. Stishovite is a high‐pressure polymorph of silica and the hardest known oxide at ambient conditions. The grain size of the composites increases with synthesis temperature from ~15 to ~750 nm. The composite is harder than alumina and the hardness increases with reducing grain size down to ~80 nm following a Hall–Petch relation. The maximum hardness with grain size of 81 nm is 23 ± 1 GPa. A softening with reducing grain size was observed below this grain size down to ~15 nm, which is known as inverse Hall–Petch behavior. The grain size dependence of the hardness might be explained by a composite model with a softer grain‐boundary phase. 相似文献
13.
Jin Zhang Tonglai Zhang Li Yang Jianguo Zhang Yan Cui Xiaochun Hu Zhenhua Liu 《Propellants, Explosives, Pyrotechnics》2009,34(1):24-31
A new coordination compound, [Mn(CHZ)3][C(NO2)3]2, was synthesized and characterized by elemental analysis, IR and UV spectra, and its crystal structure was determined by X‐ray single crystal diffraction. The crystal belongs to the triclinic system and space group with a=0.88737(18) nm, b=1.1804(2) nm, c=1.1936(2) nm, β=83.73(3)°, V=1.1121(4) nm3, Z=2, Dc=1.867 g cm−3. Every Mn(II) ion is six‐coordinated to three CHZ molecules through three carbonyl oxygen atoms and three terminal nitrogen atoms to form a distorted octahedral structure. Mn(II) ions, carbohydrazide ligand molecules, and trinitromethanide anions are jointed to a complicated three‐dimensional netted structure through coordination bonds, electrostatic forces, and extensive hydrogen bonds. The thermal decomposition character and mechanism was studied by DSC, TG‐DTG, and FTIR techniques. The non‐isothermal kinetics has also been studied on the exothermic decomposition by using Kissinger's method and Ozawa–Doyle's method. In addition, the impact, friction, and flame sensitivity data were determined. All properties data observed show that the title complex has high energy, good thermal stability, and moderately friction sensitivity. 相似文献
14.
High temperature‐insensitive ferro‐/piezoelectric properties and nanodomain structures of Pb(In1/2Nb1/2)O3–PbZrO3–Pb(Mg1/3Nb2/3)O3–PbTiO3 relaxor single crystals
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Wenhui He Qiang Li Xiaoqing Xi Qingfeng Yan 《Journal of the American Ceramic Society》2018,101(3):1236-1244
For rhombohedral (R) Pb(In1/2Nb1/2)O3–PbZrO3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PZ–PMN–PT) relaxor single crystal, high temperature‐insensitive behaviors under different external stimuli were observed (remnant polarization Pr from 30°C to 180°C and piezoelectric strain d33* from 30°C to 116°C). When electric field E ≥ 50 kV/cm in the case of an activation field Ea = 40‐50 kV/cm was applied, it was found that the domain switching was accompanied by a phase transition. The high relaxor nature of the R phase PIN–PZ–PMN–PT was speculated to account for the large Ea and high piezoelectric response. The short‐range correlation lengths extracted from the out‐of‐plane (OP) and in‐plane (IP) nanodomain images, were 64 nm and 89 nm, respectively, which proved the high relaxor nature due to In3+ and Zr4+ ions entering the B‐site in the ABO3‐lattice and enhancing the disorder of B‐site cations in the R phase PIN–PZ–PMN–PT. The switching process of R nanodomain variants under the step‐increased tip DC voltage was visually revealed. Moreover, the time‐dependent domain evolution confirmed the high relaxor nature of the R phase PIN–PZ–PMN–PT single crystal. 相似文献
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16.
ThomasM. Klaptke Konstantin Karaghiosoff Peter Mayer Alexander Penger JanM. Welch 《Propellants, Explosives, Pyrotechnics》2006,31(3):188-195
1,4‐Dimethyl‐5‐aminotetrazolium 5‐nitrotetrazolate ( 2 ) was synthesized in high yield from 1,4‐dimethyl‐5‐aminotetrazolium iodide ( 1 ) and silver 5‐nitrotetrazolate. Both new compounds ( 1, 2 ) were characterized using vibrational (IR and Raman) and multinuclear NMR spectroscopy (1H, 13C, 14N, 15N), elemental analysis and single crystal X‐ray diffraction. 1,4‐Dimethyl‐5‐aminotetrazolium 5‐nitrotetrazolate ( 2 ) represents the first example of an energetic material which contains both a tetrazole based cation and anion. Compound 2 is hydrolytically stable with a high melting point of 190 °C (decomposition). The impact sensitivity of compound 2 is very low (30 J), it is not sensitive towards friction (>360 N). The molecular structure of 1,4‐dimethyl‐5‐aminotetrazolium iodide ( 1 ) in the crystalline state was determined by X‐ray crystallography: orthorhombic, Fddd, a=1.3718(1) nm, b=1.4486(1) nm, c=1.6281(1) nm, V=3.2354(5) nm3, Z=16, ρ=1.979 g cm−1, R1=0.0169 (F>4σ(F)), wR2 (all data)=0.0352. 相似文献
17.
Chunchun Li Huaicheng Xiang Minyu Xu Jibran Khaliq Junqi Chen Liang Fang 《Journal of the American Ceramic Society》2018,101(2):773-781
Low‐firing and temperature stable microwave dielectric ceramics of Ba2LnV3O11 (Ln = Nd, Sm) were prepared by solid‐state reaction. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the phase purity, crystal structure, sintering behavior, and microstructure. The XRD patterns indicated that Ba2LnV3O11 (Ln = Nd, Sm) ceramics belong to monoclinic crystal system with P21/c space group in the whole sintering temperature range (800°C ‐900°C). Both ceramics could be well densified at 880°C for 4 hours with relative densities higher than 96%. The Ba2LnV3O11 (Ln = Nd, Sm) samples sintered at 880°C for 4 hours exhibited excellent microwave dielectric properties: εr = 12.05, Q × f = 23 010 GHz, τf = ?7.7 ppm/°C, and εr = 12.19, Q × f = 27 120 GHz, τf = ?16.2 ppm/°C, respectively. Besides, Ba2LnV3O11 (Ln = Nd, Sm) ceramics could be well co‐fired with the silver electrode at 880°C. 相似文献
18.
Suresh E. Kalathil Unnimaya A. Neelakantan Raveendran Ratheesh 《Journal of the American Ceramic Society》2014,97(5):1530-1533
Ultralow‐temperature sinterable Ba3V4O13 ceramics have been prepared through solid‐state ceramic route. Structural properties of the ceramic material are studied using powder X‐ray diffraction. Ba3V4O13 ceramic has monoclinic structure and the existence of [V4O13]6? polyhedra is confirmed through Laser Raman studies. The sample sintered at 600°C for 1 h shows dense microstructure with microwave dielectric properties of εr = 9.6, Q × f = 56 100 GHz, and τf = ?42 ppm/°C. The ceramics under study show good chemical compatibility with aluminum during cofiring. 相似文献
19.
Enhanced Piezoelectric Properties of Praseodymium‐Modified Lead‐Free (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 Ceramics
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Indrani Coondoo Neeraj Panwar Harvey Amorín Venkata Eskilla Ramana Miguel Algueró Andrei Kholkin 《Journal of the American Ceramic Society》2015,98(10):3127-3135
The role of Pr6O11 addition on the structure, microstructure, electrical, and electromechanical properties of lead‐free (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 piezoelectric ceramics has been systemically investigated. Addition of praseodymium (Pr) results in improved ferroelectric and piezoelectric properties. XRD analysis revealed the co‐existence of rhombohedral (R) and tetragonal (T) phases at room temperature. High remanent polarization values (2Pr ~17 μC/cm2) and loop squareness of nearly 0.87 were obtained for the BCZT‐0.04 wt%Pr ceramic, along with high piezoelectric coefficient (d33 = 435 pC/N) and transduction coefficient [(d33·g33) = 11589 × 10?15 m2/N]. Results are correlated with the crystal structure and microstructure that significantly influence the ferroelectric and piezoelectric properties near the R–T phase transition point. This material seems to be especially suitable for energy harvesting applications, exhibiting outstanding figure of merit. 相似文献
20.
Yan Cui Tonglai Zhang Jianguo Zhang Li Yang Jin Zhang Xiaochun Hu 《Propellants, Explosives, Pyrotechnics》2008,33(6):437-442
A novel coordination compound [Zn(DAT)2(H2O)4](PA)2⋅2H2O has been synthesized using 1,5‐diaminotetrazole (DAT) as ligands. It crystallizes in the monoclinic space group C2/c, with a=1.51973(19) nm, b=0.67904(9) nm, c=3.0712(4) nm, β=90.507(2)°, V=3.1692(7) nm3, Z=4, and μ=0.888 mm−1. With the intermolecular hydrogen bonds, molecules are linked together to form a three‐dimensional net structure. Thermal decomposition mechanism of the title compound was predicted based on DSC, TG‐DTG, and FT‐IR analyses. The kinetic parameters of the first exothermic process of the title compound were studied applying the Kissinger's and Ozawa–Doyle's methods. 相似文献