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1.
Zinc and barium phosphate glasses show good proton conductivity at intermediate temperature around 200 °C. Infrared spectra and 1H magic angle spinning-nuclear magnetic resonance (MAS–NMR) spectra proposed that a 30 mol%ZnO-70 mol%P 2O 5 glass melted at 800 °C has a large amount of ‘mobile’ protons. The proton conductivity at 250 °C was measured to be 1 × 10 −3 S/cm. A H 2-air fuel cell using the ZnO–P 2O 5 glass electrolyte of 1.8 mm in thickness showed the maximum power density of 1.2 mW/cm 2 at 200 °C. 相似文献
2.
The pyrolysis of Y(CF 3COO) 3· nH 2O at temperatures up to 1,000 °C, under flowing pure Ar, O 2 and O 2 saturated with water vapour, was extensively analysed. The formation of HF is observed directly and the existence of a :CF 2 diradical is inferred during a trifluoroacetic acid salt decomposition. High resolution thermogravimetry, differential scanning
calorimetry, X-ray diffractometry and scanning electron microscopy indicated that the exothermic one-stage decomposition of
the anhydrate salt occurs at 267 °C, forming YF 3. Fourier transform infrared spectroscopy identified (CF 3CO) 2O, CF 3COF, COF 2, CO 2 and CO as the principal volatile species; and revealed the influence of water on the reactions liberating gaseous CF 3COOH, CHF 3, HF, and SiF 4 (from reactions with glass or quartz components). NO 2 and N 2O evolution suggested that traces of CH 3NO 2 were present in the starting material. Thermogravimetry and X-ray diffractometry indicated that the slow hydrolysis of the
fluoride occurs between 630 and 655 °C, forming a mixture of Y 2O 3, YOF, Y 7O 6F 9, and YF 3. The decomposition and hydrolysis temperatures are significantly lower than previously reported, which has implications for
sol–gel processing. 相似文献
3.
The Bi 5FeTi 3O 15 (BFTO) films of layered structure have been fabricated on Pt/Ti/SiO 2/Si substrates by the sol–gel method. The thermal decomposition behaviors of precursor powder were examined using thermo-gravimetric
and differential scanning calorimeters analysis. The optimal heat treatment process for BFTO films were determined to be low-temperature
drying at 200 °C for 4 min and high-temperature drying at 350 °C for 5 min followed by annealing at 740 °C for 60 min, which
led to the formation of compact films with uniform grains of ~300 nm. The structural, surface topography, ferroelectric and
magnetic properties of the films were investigated. The remnant polarization (2 P
r) of BFTO thin films under an applied electric field of ~550 kV/cm are determined to be 67.5 μC/cm 2
. Meanwhile, the weak ferromagnetic properties of the BFTO films were observed at room temperature. 相似文献
4.
Carbon‐like nanofiber (CNF) is synthesized using microwave plasma‐enhanced chemical vapor deposition. We present the effects of fluorocarbon and oxygen (CF 4/O 2) plasma‐treated on the microstructural, crystal, and field emission (FE) characteristics of CNF by SEM, transmission electron microscopy, micro‐Raman, and FE system. Results showed that the presence of the damaged CNF occurs at 2 min CF 4/O 2 plasma treatment and some amorphous carbon particles after 10 min CF 4/O 2 plasma treatment. One can also observe that turn‐on fields were enhanced (2.75 uA/cm 2) at 2 min CF 4/O 2 plasma treatment; this indicates a remarkable FE enhancement of the local emission region in CNFs. Complementary information was obtained by thermal desorption atmospheric pressure ionization mass spectrometry and XPS. It can be found that the broken surface morphologies could be attributed to the chemical reaction exchanged via plasma excitation; a large number of bonding (C–F and C–O) in the CNF was detected. In addition, it is observed that the CNF has higher fluorine desorbed at 277.5 and 427 °C after CF 4/O 2 plasma treatment. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
5.
Chemical preparation methods, X-ray diffraction and vibrational data are reported for six triphosphates type M IINa 3P 3O 10.12H 2O (M II = Cu, Ni and Mg) and their anhydrous forms M IINa 3P 3O 10. These condensed phosphates are respectively, CuNa 3P 3O 10.12H 2O, MgNa 3P 3O 10.12H 2O, NiNa 3P 3O 10.12H 2O, CuNa 3P 3O 10, NiNa 3P 3O 10 and MgNa 3P 3O 10. The hydrate triphosphates were prepared by the method of ion-exchange resin, where as their anhydrous forms were prepared by total thermal dehydration of M IINa 3P 3O 10.12H 2O (M II = Cu, Ni and Mg).CuNa 3P 3O 10.12H 2O, MgNa 3P 3O 10.12H 2O and NiNa 3P 3O 10.12H 2O are isotypic, and crystallize in the monoclinic system, space group is P2 1/n, Z = 4, the unit-cell parameters are: CuNa3P3O10.12H2O, a = 15.052(8) Å, b = 9.234(3) Å,c = 14.767(8) Å and β = 90.03(5)°. MgNa3P3O10.12H2O: a = 15.049(1) (1) Å, b = 9.245(4) Å, c = 14 0.722(3) (2) Å and β = 90.00(5)°.NiNa 3P 3O 10.12H 2O: a = 15.010(1) Å, b = 9.208(4) Å, c = 14.710(2) Å and β = 90.00(5)°.The anhydrous forms CuNa 3P 3O 10, MgNa 3P 3O 10 and NiNa 3P 3O 10 crystallize in the monoclinic system, space group is P2 1/n, Z = 4, the unit-cell parameters are: CuNa 3P 3O 10, a = 12.464(0) Å, b = 8.437(7) Å, c = 12.083(1) Å and β = 109.77(8) °; MgNa 3P 3O 10: a = 11.931(4) (1) Å, b = 12.912(2) Å, c = 10.057(0) Å and β = 113.83(2)° and NiNa 3P 3O 10: a = 12.686(8)Å, b = 9.271(2) (4) Å, c = 11.440(3) Å and β = 102,95(5)°. 相似文献
6.
Conversion of CF4 was experimentally evaluated with three systems including catalytic hydrolysis, NTP-alone and plasma catalysis. Firstly, activity of γ-Al2O3 for CF4 conversion was tested via catalytic hydrolysis. Experimental results indicate that the highest CF4 conversion (72%) could be achieved with γ-Al2O3 in the presence of 45% H2O(g) with the operating temperature of 900 °C and the apparent activation energy is calculated as 85 kJ/mol using power rate law model. For plasma-based systems, results indicate that CF4 conversions achieved with plasma catalysis remain 100% with the applied voltage ranging from 12 to 23 kV, while the highest CF4 conversion achieved with NTP-alone is 86%. For the effects of various parameters on plasma-based systems, the results indicate that plasma catalysis also has better resistivity for higher total flow rate, CF4 concentration and O2 contents. Especially, CF4 conversion could maintain at 100% with the operating applied of 23 kV as CF4 concentration is increased to 10,000 ppm. On the other hand, CF4 conversion achieved with NTP-alone is 18% at the same conditions. In addition, negative effect of O2 on plasma catalysis could be reduced by the addition of Ar due to its good discharge properties and high excitation threshold energy (13 eV). The kinetics of plasma catalysis is investigated for CF4 conversion by a simplified model, and the results indicate that overall energy constant achieved with plasma catalysis reaches 0.015 mg J?1. Overall, plasma catalysis is demonstrated with good potential for the reduction of CF4 emission. 相似文献
7.
Plasma processing of metallic cobalt was experimentally investigated with three fluorine-containing gases, CF 4–O 2, SF 6–O 2, and NF 3 to determine the surface decontamination rate and to examine the reaction mechanism. Results show that the maximum etching
rate reaches 17.12 μm/min with NF 3 gas at 420°C, while the rates are 2.56 μm/min and 1.14 μm/min with CF 4–O 2 and SF 6–O 2 gas, respectively, at the same temperature. AES analysis identified the constituent elements of the reaction products to
be oxygen, fluorine, and cobalt, and XPS analysis reveals that the reaction product with all three plasma gases is very likely
to be CoF 2. 相似文献
8.
The chemical composition and components of a polytetrafluoroethylene (PTFE) surface was investigated as a function of the temperature under the irradiation of synchrotron radiation (SR) by the X-ray photoelectron spectroscopy (XPS). When the temperature of PTFE under the SR irradiation was less than 100 °C, the C-rich surface appeared. With increasing the temperature more than 150 °C, the relative intensity of the F 1 s peak to the C 1 s peak increased markedly. At the temperatures of 150–180 °C, the C–C component became small and the CF 2 component was dominant. With further increasing the temperature more than 200 °C, CF 3, CF and C–CF components grew in addition to CF 2 component. Based on these XPS results, the temperature effect on the chemical composition and components is discussed. 相似文献
9.
The phase stability, nonstoichiometry and point defect chemistry of polycrystalline Sr 2FeMoO 6?δ (SFMO) was studied by thermogravimety at 1000, 1100, and 1200 °C. Single-phase SFMO exists between ?10.2≤log pO 2≤?13.7 at 1200 °C. At lower oxygen partial pressure a mass loss signals reductive decomposition. At higher pO 2 a mass gain indicates oxidative decomposition into SrMoO 4 and SrFeO 3?x. The nonstoichiometry δ at 1000, 1100, and 1200 °C was determined as function of pO 2. SFMO is almost stoichiometric at the upper phase boundary (e.g. δ=0.006 at 1200 °C and log pO 2=?10.2) and becomes more defective with decreasing oxygen partial pressure (e.g. δ=0.085 at 1200 °C and log pO 2=?13.5). Oxygen vacancies are shown to represent majority defects. From the temperature dependence of the oxygen vacancy concentration the defect formation enthalpy was estimated (Δ HOV=253±8 kJ/mol). Samples of different nonstoichiometry δ were prepared by quenching from 1200 °C at various pO 2. An increase of the unit cell volume with increasing defect concentration δ was found. The saturation magnetization is reduced with increasing nonstoichiometry δ. This demonstrates that in addition to Fe/Mo site disorder, oxygen nonstoichiometry is another source of reduced magnetization values. 相似文献
10.
The
mineral sabugalite (HAl) 0.5[(UO 2) 2(PO 4)] 2⋅8H 2O, has been studied using a combination of energy
dispersive X-ray analysis, X-ray diffraction, dynamic and controlled rate
thermal analysis techniques. X-ray diffraction shows that the starting material
in the thermal decomposition is sabugalite and the product of the thermal
treatment is a mixture of aluminium and uranyl phosphates. Four mass loss
steps are observed for the dehydration of sabugalite at 48°C (temperature
range 39 to 59°C), 84°C (temperature range 59 to 109°C), 127°C
(temperature range 109 to 165°C) and around 270°C (temperature range
175 to 525°C) with mass losses of 2.8, 6.5, 2.3 and 4.4%, respectively,
making a total mass loss of water of 16.0%. In the CRTA experiment mass loss
stages were found at 60, 97, 140 and 270°C which correspond to four dehydration
steps involving the loss of 2, 6, 6 and 2 moles of water. These mass losses
result in the formation of four phases namely meta(I)sabugalite, meta(II)sabugalite,
meta(III)sabugalite and finally uranyl phosphate and alumina phosphates. The
use of a combination of dynamic and controlled rate thermal analysis techniques
enabled a definitive study of the thermal decomposition of sabugalite. While
the temperature ranges and the mass losses vary due to the different experimental
conditions, the results of the CRTA analysis should be considered as standard
data due to the quasi-equilibrium nature of the thermal decomposition process.
The online version of the original article can be found at 相似文献
11.
A phase equilibria diagram of the partial system NdPO 4–K 3PO 4–KPO 3 has been developed as part of the research aimed at determining the phase equilibrium relationships in the oxide system Nd 2O 3–K 2O–P 2O 5. The investigations were conducted using thermoanalytical techniques, X-ray powder diffraction analysis and reflected-light microscopy. Three isopleths existing between: K 3Nd(PO 4) 2–K 4P 2O 7, NdPO 4–K 5P 3O 10 and NdPO 4–K 4P 2O 7 have been identified in the partial NdPO 4–K 3PO 4–KPO 3 system. Previously unknown potassium-neodymium phosphate “K 4Nd 2P 4O 15” has been discovered in the latter isopleth section. This phosphate exists in the solid phase up to a temperature of 890 °C at which it decomposes into the parent phosphates NdPO 4 and K 4P 2O 7. Four invariant points: two quasi-ternary eutectics, E 1 (1057 °C) and E 2 (580 °C) and two quasi-ternary peritectics, P 1 (1078 °C) and P 2 (610 °C), occur in the NdPO 4–K 3PO 4–KPO 3 region. 相似文献
12.
This paper employs the SAXS technique to study the microstructure evolution of nano Al 2O 3/low-density polyethylene (LDPE) composite film during temperature increase and decrease (including interfacial layer thickness, mass fractal and surface fractal), and discusses the deformation memory effect (DME) mechanism. Compared with the case of pure LDPE, there are some new phenomena observed in the Al 2O 3/LDPE composite film, such as an interfacial layer and surface fractal. The experimental results showed that, when the temperature rose from 25 °C to 180 °C, the interfacial layer thickness of the composite film increased from 2.8 nm to 3.5 nm, and the surface fractal dimension increased from 1.2 to 2.0, with the lamellar crystal of the PE molecular chains melting. When the temperature dropped from 180 °C to 30 °C, the interfacial layer thickness decreased from 3.5 nm to 3.0 nm, and the surface fractal dimension changed from 2.0 to 1.2, with the PE molecular chains recrystallizing. We found that the DME of the interface layer is that thickness and area increase when temperature rises and decrease when temperature decreases. The addition of Al 2O 3 nanoparticles into the polymer results in the adsorption of space charges in the matrix onto the nanoparticles and in the interfacial regions, which efficiently inhibits the space charge accumulation of the composite material in the gradient electrical field. 相似文献
13.
Thermal decomposition of a mixed valence copper salt, Na 4[Cu(NH 3) 4][Cu(S 2O 3) 2] 2·0.5NH 3 ( 1) prepared from pentahydrates of sodium thiosulfate and copper sulphate of various molar ratios in 1:1 v/v aqueous ammonia
solution, has been studied up to 1,000 °C in flowing air by simultaneous thermogravimetric and differential thermal analysis
coupled online with quadrupole mass spectrometer (TG/DTA-MS) and FTIR spectrometric gas cell (TG-FTIR), in comparison. Compound
1 releases first but very slowly some of the included ammonia till 170 °C, then simultaneously ammonia (NH 3) and sulphur dioxide (SO 2) from 175 to 225 °C, whilst the evolution of SO 2 from thiosulfate ligands continues in several overlapping stages until 410 °C, and is escorted by explicit exothermic heat
effects at around 237, 260, 358 and 410 °C. The former two exothermic DTA-peaks correspond to the simultaneous degradation
and air oxidation processes of excess thiosulfate anions not reacted by formation of copper sulfides (both digenite, Cu 1.8S and covellite, CuS, checked by XRD) and sodium sulfate, while the last two exothermic peaks are accompanied also by considerable
mass gains, as the result of two-step oxidation of copper sulfides into various oxosulfates. The mass increase continues further
on until 580 °C, when the sample mass begins to decrease slowly, as a continuous decomposition of the intermediate copper
oxosulfates, indicated also by re-evolution of SO 2. At 1,000 °C, a residual mass value of 64.3% represents a stoichiometric formation of Cu IIO and anhydrous Na 2SO 4. 相似文献
14.
Highly crystalline niobium- and tantalum-based oxynitride perovskite nanoparticles were obtained from hydrothermally synthesized oxide precursors by thermal ammonolysis at different temperatures. The samples were studied with respect to their morphological, optical and thermal properties as well as their photocatalytic activity in the decomposition of methyl orange. Phase pure oxynitrides were obtained at rather low ammonolysis temperatures between 740 °C (CaNbO 2N) and 1000 °C (BaTaO 2N). Particle sizes were found to be in the range 27 nm–146 nm and large specific surface areas up to 37 m 2 g −1 were observed. High photocatalytic activities were found for CaNbO 2N and SrNbO 2N prepared at low ammonolysis temperatures. CoO x as co-catalyst was loaded on the oxynitride particles resulting in a strong increase of the photocatalytic activities up to 30% methyl orange degradation within 3 h for SrNbO 2N:CoO x. 相似文献
15.
A representative series of diphosphine monophosphonium salts [1‐Ph 2P(C 10H 6)‐8‐PRPh 2] +X – ( 2 b : R = H, X = CF 3SO 3; 4 : R = Me, X = CF 3SO 3; 5 : R = C 6H 5CH 2 = Bn, X = Br) has been prepared by treatment of 1,8‐bis(diphenylphosphino)naphthalene (dppn, 1 ) with stoichiometric amounts of HSO 3CF 3 or CH 3SO 3CF 3 in CH 2Cl 2 at +20 °C and with C 6H 5CH 2Br in toluene at +80 °C. Their X‐ray crystal structures show that there is no evidence for dative P → P + interactions. Instead, steric repulsion deflects the substituent groups to opposite faces of the naphthalene plane [splay angles: +11.4° ( 2 b ), +13.6° ( 4 ); +16.7° ( 5 )]. In solution 2 b , 4 , and 5 were dynamic according to 31P, 13C, and 1H NMR spectroscopy. The fluxionality of 2 b involves rapid intramolecular proton exchange between the two phosphorus atoms, which slows down at low temperature, whereas the dynamic behaviour of 4 and 5 is interpreted in terms of hindered rotation of the bulky RPh 2P + groups (R = Me or Bn) about the P–C(naphthyl) bond. Treatment of 1,8‐bis(diphenylphosphoryl)naphthalene (dppnO 2, 6 ) with HSO 3CF 3 gave the protonated bis(phosphine oxide), as the triflate salt, dppnO 2H + CF 3SO 3– ( 7 ). The X‐ray structure analysis of 7 revealed a highly strained molecule (P1…P2 365.5 pm) in which the P=O bonds point to the same face of the naphthalene plane to accommodate the proton. All isolated compounds were characterised by a combination of 31P, 1H, and 13C NMR spectroscopy, IR spectroscopy ( 7 ), mass spectrometry and elemental analysis. 相似文献
16.
We report a new low temperature method for the synthesis of LnNiO 3 (Ln = Eu, Gd) at 400 °C under 180 bar oxygen pressure with the flux method. Utilization of the LiCl/KCl flux allowed for a decrease of the reaction temperature from 1000 °C and resulted in the synthesis of pure phase compounds. These materials have been characterized by powder X-ray diffraction and thermogravimetric analysis. LnNiO 3 (Ln = Eu and Gd) compounds crystallize in the orthorhombic GdFeO 3-type perovskite structure (space group: Pbnm). Both materials decompose to Ln 2O 3 and NiO at 775 °C under a nitrogen atmosphere and undergo reduction to Ln 2O 3 and Ni metal (at 385 °C and 340 °C for Eu and Gd, respectively) under a hydrogen atmosphere (10% H 2/N 2). Attempts to prepare the first T′-type infinite layer compound with Ni 2+, EuNiO 2, by low temperature reduction of EuNiO 3 were unsuccessful. 相似文献
17.
C s-C 60(CF 3) 6 was synthesized by the reaction of S 6-C 60(CF 3) 12 with C 60 at 530 °C. Its molecular structure with skew-pentagonal- pyramidal addition pattern was elucidated by single crystal X-ray diffraction. Theoretical DFT calculations were performed to account for a high degree of fragmentation in negative-ion mass spectra. 相似文献
18.
During the search for selenium analogues of FeTe 2O 5Cl, the new iron (III) tellurate(IV) selenate(IV) chloride with the composition Fe[(Te 1.5Se 0.5)O 5]Cl was synthesized by chemical vapor transport (CVT) reaction and characterized by TGA-, EDX-,SCXRD-analysis, as well as IR and Raman spectroscopy. It was found that Fe[(Te 1.5Se 0.5)O 5]Cl crystallizes in the monoclinic space group P2 1/ c with unitcell parameters a = 5.183(3) Å, b = 15.521(9) Å, c = 7.128(5) Å and β = 107.16(1)°. The crystal structure of Fe[(Te 1.5Se 0.5)O 5]Cl represents a new structure type and contains electroneutral heteropolyhedral layers formed by dimers of the [FeO 5Cl] 8– octahedra, linked via common O-O edges, and mixed [Te 3SeO 10] 4- tetramers. Adjacent layers are stacked along the b axis and linked by weak residual bonds. The new compound is stable up to 420 °C. DFT calculations predict Fe[(Te 1.5Se 0.5)O 5]Cl to be a wide-gap semiconductor with the band gap of ca. 2.7 eV. 相似文献
19.
Three halotrichites namely halotrichite Fe 2+SO 4·Al 2(SO 4) 3·22H 2O, apjohnite Mn 2+SO 4·Al 2(SO 4) 3·22H 2O and dietrichite ZnSO 4·Al 2(SO 4) 3·22H 2O, were analysed by both dynamic, controlled rate thermogravimetric and differential thermogravimetric analysis. Because of
the time limitation in the controlled rate experiment of 900 min, two experiments were undertaken (a) from ambient to 430 °C
and (b) from 430 to 980 °C. For halotrichite in the dynamic experiment mass losses due to dehydration were observed at 80,
102, 319 and 343 °C. Three higher temperature mass losses occurred at 621, 750 and 805 °C. In the controlled rate thermal
analysis experiment two isothermal dehydration steps are observed at 82 and 97 °C followed by a non-isothermal dehydration
step at 328 °C. For apjohnite in the dynamic experiment mass losses due to dehydration were observed at 99, 116, 256, 271
and 304 °C. Two higher temperature mass losses occurred at 781 and 922 °C. In the controlled rate thermal analysis experiment
three isothermal dehydration steps are observed at 57, 77 and 183 °C followed by a non-isothermal dehydration step at 294 °C.
For dietrichite in the dynamic experiment mass losses due to dehydration were observed at 115, 173, 251, 276 and 342 °C. One
higher temperature mass loss occurred at 746 °C. In the controlled rate thermal analysis experiment two isothermal dehydration
steps are observed at 78 and 102 °C followed by three non-isothermal dehydration steps at 228, 243 and 323 °C. In the CRTA
experiment a long isothermal step at 636 °C attributed to de-sulphation is observed. 相似文献
20.
Highly (100)-oriented Pb 0.8La 0.1Ca 0.1Ti 0.975O 3 (PLCT) thin films deposited on Pt/Ti/SiO 2/Si substrate were successfully achieved by a sol–gel route. The influence of annealing temperature on microstructures and
electric properties was investigated; it was found that the PLCT film could be crystallized only at 450 °C. When the annealing
temperature increased to 500 °C, the PLCT film exhibited highly (100)-oriented, which also possessed higher remnant polarization
Pr (27 μC/cm 2) and better pyroelectric figure of merit ( F
d = 205 μC/m 2k) at room temperature. It was also found too high annealing temperature (625 °C) could lead to recrystallization of film,
and the small grains caused by recrystallization could make polarization reversal difficult and disturbed the preferred crystal
growth in film, which was not benefit to obtain enhanced electric properties. 相似文献
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