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1.
V. V. Martsinkevich V. G. Ponomareva T. N. Drebushchak G. V. Lavrova S. S. Shatskaya 《Inorganic Materials》2010,46(7):765-769
Cs1 − x
Rb
x
H2PO4 solid solutions have been synthesized for the first time in a broad composition range, x = 0.03–0.9. At room temperature, the Cs1 − x
Rb
x
H2PO4 solid solutions are isostructural with the low-temperature phase of CsH2PO4 over the entire composition range studied. In the CsH2PO4-based solid-solution series, the unit-cell parameters and volume decrease with increasing Rb content. At high temperatures,
the Cs1 − x
Rb
x
H2PO4 solid solutions exist in the range x = 0–0.4, are isostructural with cubic CsH2PO4, and have a smaller unit-cell parameter. 相似文献
2.
(1 − x)BiFeO3 · x(KBi)1/2TiO3 ceramics have been prepared by solid-state reactions. The system has been shown to contain a continuous series of perovskite
solid solutions. In the composition ranges x < 0.4, 0.4 < x < 0.9, and x > 0.9, the solid solutions have rhombohedral, orthorhombic, and tetragonal structures, respectively. The observed compositional
phase transitions are accompanied by sharp changes in unit-cell volume. We describe the dielectric properties of the orthorhombic
solid solutions, which demonstrate that these materials exhibit relaxor behavior. 相似文献
3.
The physicochemical properties of (1 − x)CsH2PO4/xSiP
y
O
z
(x = 0.2–0.7) composites containing fine-particle silicon phosphates as heterogeneous additives have been studied at different
humidities. The introduction of silicon phosphates suppresses the superionic phase transition of CsH2PO4 and increases the low-temperature conductivity of the materials, which depends significantly on humidity. The CsH2PO4-SiP
y
O
z
materials offer high conductivity (∼3 × 10−3 to 10−2 S/cm at ∼110–230°C) at low water vapor pressures (3 mol % H2O). Amorphization of the CsH2PO4 in the composites markedly changes its thermodynamic properties. The effect of long-term isothermal holding (210°C, 3 mol
% H2O) on the conductivity of the composites has been studied.
Original Russian Text ? V.G. Ponomareva, E.S. Shutova, G.V. Lavrova, 2008, published in Neorganicheskie Materialy, 2008, Vol.
44, No. 9, pp. 1131–1136. 相似文献
4.
We have synthesized materials based on a silver titanium phosphate with partial substitution of tri-, tetra-, or pentavalent
cations for titanium: Ag1±x
Ti2−x
M
x
(PO4)3 (M = Nb5+, Ga3+) and AgTi2−x
Zr
x
(PO4)3. The materials have been characterized by X-ray diffraction and impedance spectroscopy and have been shown to have small
thermal expansion coefficients. Their ionic conductivity has been determined. Silver ions in these materials are difficult
to replace with protons. 相似文献
5.
Ternary perovskite ceramics of Pb[(Zr0.5Ti0.5)0.8−x
(Mg1/3Nb2/3)0.2+x]0.98Nb0.02O3.01 (PZTMN, x = −0.075, −0.05, −0.025, 0, 0.025, 0.05, and 0.075 ), are synthesized via dry–dry method. B-site precursors of PZTMN ([(Zr0.5Ti0.5)0.8−x
(Mg1/3Nb2/3)0.2+x
]0.98Nb0.02O2.01, ZTMN) can be synthesized via a two-step solid state reaction method. The first calcination temperature is 1,300 °C, and
the second is not higher than 1,360 °C. Incorporation of magnesium and niobium ions promotes the formation of the single phase
solid solution with ZrTiO4 structure. Single phase perovskite PZTMN is formed at 780 °C, much lower than that in conventional process. Dense ceramics
can be sintered at about 1,260 °C with dielectric and piezoelectric properties comparable to that of wet–dry method and higher
than that of conventional method. It seems that B-site precursor method is cost effective in preparation of ternary piezoelectric
ceramics. 相似文献
6.
(1 − x) KNbO3 · xBiMg2/3Nb1/3O3 ceramic materials have been prepared by solid-state reactions. The materials with x < 0.3 have been shown to be perovskite solid solutions. Their average lattice parameter increases linearly with x. Like undoped KNbO3, the solid solutions undergo a low-temperature (rhombohedral → orthorhombic) ferroelectric phase transition. The transition
temperature increases almost linearly with x. The dc electrical conductivity of the ceramics exhibits Arrhenius behavior. The activation energy for conduction rises sharply
near the phase transition temperature. 相似文献
7.
S. M. Levshov I. V. Berezovskaya N. P. Efryushina B. I. Zadneprovskii V. P. Dotsenko 《Inorganic Materials》2011,47(3):285-289
We have studied the luminescence spectra of Li2Sr1 − x
Eu
x
SiO4 (x = 0.0001–0.01) solid solutions prepared by solid-state reactions and a sol-gel process in a reducing atmosphere. The spectra
show a broad band in the range 500–700 nm, centered at 578 nm, which is due to the 4f
65d → 4f
7 transition. The luminescence excitation spectrum shows, in addition to bands due to Eu2+ 4f
7 → 4f
65d transitions, a strong band centered at 174 nm, attributable to absorption in the SiO44− group. 相似文献
8.
M. M. Sinha 《Bulletin of Materials Science》2002,25(6):459-462
In recent years, the fluorite-structured solid solutions with the general formula, (MF2)1-x(RF3)x (M = Ca, Sr, Ba, Pb and R is a rare-earth element or Y), have been the subject of numerous experimental studies focussed
on their superionic properties. The overall cubic crystal symmetry (space group Fm3m) is conserved up to x ≶ xmax, where xmax ⊁ 0.4-0.5 depending on M and R. The zone centre phonons and phonon dispersion along three symmetry directions of the mixed
superionic compound (BaF2)1-x(LaF3)x have been investigated by applying de Launey angular force model for x ≶ xmax. The calculated results are compared and explained with available experimental results. 相似文献
9.
Solid solution of (1−x)LaCrO3–xBiCrO3 (x = 0, 0.10, 0.15, 0.20 and 0.25) was prepared via the citrate–nitrate combustion synthesis. Pure perovskite phase was obtained
at 800 °C, a much lower synthesis temperature than that needed in the solid-state reactions. The thermodynamics of phase formation
and the ceramic sintering mechanism were investigated. The substitution of Bi3+ for La3+ was found to give a separate exothermic decomposition event in the gels and the precursor did not produce a transient liquid
phase while heating to 1200 °C, as was found in ceramics prepared by solid state reaction. This finding shows that the role
of Bi2O3 in the sintering of the La1−x
Bi
x
CrO3 ceramics depends on the processing method. 相似文献
10.
Josef Jirák Ladislav Koudelka Jaroslav Pospíšil Petr Mošner Lionel Montagne Laurent Delevoye 《Journal of Materials Science》2007,42(20):8592-8598
Glasses of the ternary system ZnO–Bi2O3–P2O5 were prepared and studied in two compositional series 50ZnO–xBi2O3–(50 − x)P2O5 and (50 − y)ZnO–yBi2O3–50P2O5. Two distinct glass-forming regions were found in the 50ZnO–xBi2O3–(50 − x)P2O5 glass series with x = 0–10 and 20–35 mol.% Bi2O3. All prepared Bi2O3-containing glasses reveal a high chemical durability. Small additions of Bi2O3 (∼5 mol.%) improve thermal stability of glasses. All glasses crystallize on heating within the temperature range of 505–583 °C.
Structural studies by Raman and 31P MAS NMR spectroscopies showed the rapid depolymerisation of phosphate chains within the first region with x = 0–15 and the presence of isolated Q0 phosphate units within the second region with x = 20–35. Raman studies showed that bismuth is incorporated in the glass structure in BiO6 units and their vibrational bands were observed within the spectral region of 350–700 cm−1. The evolution of properties and the spectroscopic data are both in accordance with a network former effect of Bi2O3. 相似文献
11.
G. D. Nipan V. A. Ketsko A. I. Stognij A. V. Trukhanov T. N. Kol’tsova M. A. Kop’eva L. V. Elesina N. T. Kuznetsov 《Inorganic Materials》2010,46(4):429-433
Using pyrohydrolytic synthesis, we have obtained a continuous series of Mg(Fe1 − x
Ga
x
)2O4 + δ solid solutions, as checked by X-ray diffraction. The magnetization and coercivity of the samples have been determined from
field dependences in applied magnetic fields of ±5 T, and their conductivity has been assessed using current-voltage measurements
at 300 K in electric fields from −200 to +200 V. The effective band gap of the solid solutions has been evaluated from their
absorption spectra obtained by diffuse reflectance measurements. The optimal composition for spintronic applications is Mg(Fe0.8Ga0.2)2O4 + δ. 相似文献
12.
Caixuan Xu Anming Hu Naomichi Sakai Izumi Hirabayashi Mitsuru Izumi 《Journal of Superconductivity and Novel Magnetism》2007,20(4):309-314
Single domain GdBa2Cu7-δ (Gd123) bulk superconductors were fabricated in air by top-seeding melt-texture growth. Performance of the air-processed
Gd123 was successfully enhanced by addition of both BaCO3 and BaCuO2−x
, which suppress the formation of Gd1+x
Ba2−x
Cu3O7-δ solid solutions. The optimum doping amount ranges from 0.05 to 0.15, M BaCO3 and 0.05 to 0.1, M BaCuO2−x
per molar Gd123. The distribution of the second phase particles was observed by scanning electron microscopy. A narrow band
formed by Gd2BaCuO5 particle concentration appeared around the seeding zone in both a–b plane and c-growth sector in Gd123 single grain. Trapped magnetic field density reached 0.67, T for sample with 24 mm in diameter and
8, mm in thickness and a high critical current density J
c up to 91,200, A/cm2 was achieved at 77, K under self-field. 相似文献
13.
V. G. Ponomareva I. N. Bagryantseva G. V. Lavrova N. K. Moroz 《Inorganic Materials》2014,50(7):716-722
A detailed investigation of the highly conductive Cs(H2PO4)1?x (HSO4) x (x = 0.15–0.3) proton electrolyte, its structural properties, and ageing behavior was carried out using X-ray diffraction, DSC, and impedance and NMR spectroscopy. The high conductivity of electrolytes (~2 × 10?2 S/cm) remains stable during long-term ageing at 180–200°C due to stabilization of the high temperature phase to lower temperatures. The room temperature 1H MAS NMR spectrum of (CsH2PO4)1?x (CsHSO4) x demonstrates the predominantly highly mobile protons present in these materials with the residual low-mobile protons, which agrees with the XRD data. According to XRD and 1H NMR data, the cubic phase of Cs(H2PO4)1 ? x (HSO4) x (x = 0.15–0.3) that stabilizes at room temperature gradually transforms to a low-temperature monoclinic one. The kinetics of the phase transformation for mixed salt depends markedly on the relative air humidity. A possible stabilization mechanism of the Cs(H2PO4)1 ? x (HSO4) x superionic phase with high proton mobility at low temperatures is discussed. 相似文献
14.
O. Ya. Manashirov A. N. Georgobiani V. B. Gutan E. M. Zvereva A. N. Lobanov 《Inorganic Materials》2012,48(7):721-726
We have established the key trends in the variation of the intensity of the visible and IR luminescence of (Y1 − x − y − z Yb x Tm y Er z )2O2S solid solutions in relation to their composition under laser excitation at λ = 0.940 μm. The results obtained have been used to develop multifunctional anti-Stokes white phosphors with various tinges and a predetermined relative intensities of visible and IR emission bands. 相似文献
15.
Yu. V. Stadnyk A. M. Goryn’ Yu. K. Gorelenko L. P. Romaka N. A. Mel’nichenko 《Inorganic Materials》2010,46(8):842-846
Ti1 − x
V
x
NiSn (x = 0–0.10) substitutional solid solutions have been prepared by doping the intermetallic semiconductor n-TiNiSn (half-Heusler phase) with vanadium, a donor impurity, and their resistivity and thermopower have been measured at
temperatures from 80 to 380 K. The results demonstrate that, when doping of TiNiSn causes no type inversion, the thermoelectric
power factor of the solid solution markedly exceeds that of the undoped ternary compound. 相似文献
16.
Series of glass based on the (80 − x)TeO2–20ZnO–(x)Er2O3 system (0.5 mol% ≤ x ≤ 2.5 mol%) has successfully been made by melt quenching technique. The optical properties of glass have been investigated
by means of IR and Raman spectroscopy. It is observed that as the Er2O3 content is being increased, the sharp IR absorption peaks are consistently shifted from 650 to 672 cm−1 while the Raman shift intensity around 640–670 cm−1 is decreases but increases around 720–740 cm−1. It is found out that both phenomenons are related to the structural changes between the stretching vibration mode of TeO4 tbp and TeO3 tp, and bending vibration mode of Te–O bonds in the glass linkages. 相似文献
17.
Yu. V. Stadnyk A. M. Goryn’ V. V. Romaka Yu. K. Gorelenko L. P. Romaka N. A. Mel’nichenko 《Inorganic Materials》2011,47(6):637-644
We have studied the electronic and crystal structures and temperature-dependent resistivity and thermopower of Zr1 − x
Er
x
NiSn (x = 0–0.20) substitutional semiconductor solid solutions (so-called half-Heusler alloys) in the temperature range 80–380 K.
Heavily erbium doped semiconductors with the MgAgAs structure are described in terms of an amorphous semiconductor model.
The erbium atoms in Zr1 − x
Er
x
NiSn are shown to act as acceptors. Density of states calculation results for the Zr1 − x
Er
x
NiSn alloys are consistent with experimental data. 相似文献
18.
New dielectric ceramics in the SrLa4−xSmxTi5O17 (0 ≤ x ≤ 4) composition series were prepared through a solid state mixed oxide route to investigate the effect of Sm+3 substitution for La+3 on the phase, microstructure and microwave dielectric properties. At x = 0–3, all the compositions formed single phase ceramics
within the detection limit of in-house X-ray diffraction when sintered in the temperature range 1500–1580 °C. At x = 4, a
mixture of Sm2Ti2O7 and SrTiO3 formed. The maximum Sm+3-containing single phase ceramics, SrLaSm3Ti5O17, exhibited relative permittivity (εr) = 42.6, temperature coefficient of resonant frequency (τ
f
) = −96 ppm/oC and quality factor (Q
u
f
o
) = 7332 GHz. An analysis of results presented here indicates that SrLa4−xSmxTi5O17 ceramics, exhibiting τ
f
~ 0 and εr ~ 53 could be achieved at x ~ 1.4 but at the cost of decrease in Q
u
f
o
. 相似文献
19.
This paper describes the synthesis and spectroscopic studies of the glass system, 20Na2O-(20-x) ZnO-xZnF2-60B2O3(x = 0, 5, 10, 15, 20), prepared by melt quenching method. The analyses of DSC and XRD did not show the crystallinity of the
glass sample. 11B MAS-NMR shows the presence of sharp peak around −14 ppm. From the IR studies, the broadening of the peak around 1200–1400
and 800–1100 cm−1 shows the presence of mixed linkages like B-O-B, B-O-Zn in the network. 相似文献
20.
O. Ya. Manashirov A. N. Georgobiani V. B. Gutan E. M. Zvereva A. N. Lobanov 《Inorganic Materials》2011,47(9):1006-1011
We have identified general relationships between the spectral and kinetic properties of the IR Stokes luminescence bands of
Y1 − x − y
Nd
x
Pr
y
PO4 solid solutions in the spectral range 0.86–1.40 μm under 0.810-μm laser excitation. The results have been used to formulate
technical requirements for the purity of rare-earth oxides for the fabrication of efficient YPO4:Nd3+ IR phosphors and to develop a fast YPO4:Nd3+, Pr3+ IR phosphor that allows the decay time of the Nd3+ IR Stokes luminescence bands in the range 0.86–1.40 μm to be tuned from 50 to 170 μs by varying the ratio of the Nd3+ and Pr3+ concentrations. 相似文献