High temperature X-ray diffraction studies of the decomposition mechanism of YBa2Cu3O7−δ at an oxygen partial pressure less than 10 Pa

1995 ◽  
Vol 10 (3) ◽  
pp. 165-169 ◽  
Author(s):  
W. Pitschke ◽  
W. Bieger ◽  
G. Krabbes ◽  
U. Wiesner
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Solid State Reaction ◽  
Peritectic Reaction ◽  
Decomposition Reaction ◽  
Primary Decomposition ◽  
X Ray Diffraction ◽  
X Ray

The crystallographic data of YBa2Cu3O7−δ, Y2BaCuO5, BaCu2O2, and YBa4Cu3O9 at high temperatures and p(O2)<10 Pa have been derived on the basis of HT-XRD measurements. Whereas Y2BaCuO5 expands nearly isotropically, YBa2Cu3O7−δ and BaCu2O2 show anisotropic expansions. Furthermore, the first decomposition step of the considered compounds at p(O2)<10 Pa was observed. BaCu2O2 melts congruently at T ≍ 1273 K and Y2BaCuO5 decomposes via a peritectic reaction into Y2O3, Y2BaO4 and melts at T ≍ 1323 K. A solid-state reaction into Y2BaCuO5 and BaCu2O2 was indicated for YBa2Cu3O7−δ at T ≍ 1123 K. Because YBa4Cu3O9 becomes unstable at T ≍ 1123 K, this compound cannot be formed by the primary decomposition reaction of YBa2Cu3O7−δ

Superconducting Compound Hg0.8Sb0.2Ba2Ca2Cu3O8+δ Compared with Hg0.8Sb0.2Ba2Ca1Cu2O6+δ to Evaluate Transition Temperature

2020 ◽  
Vol 18 (11) ◽  
pp. 14-18
Author(s):  
Abbas K. Saadon ◽  
Kareem A. Jasim ◽  
Auday H. Shaban
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Solid State ◽  
Solid State Reaction ◽  
Hot Spot ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Superconducting Compound

The high temperature superconductor’s compounds are one of the hot spot field of science, due to their applications in industries. Hg0.8Sb0.2Ba2Ca2Cu3O8+δ and Hg0.8Sb0.2Ba2Ca1Cu2O6+δ, were manufactured using a doable-step of solid state reaction method. The samples were sintered at 800 ° C. The transition temperatures Tc are found from electrically resistively by using four probe techniques. The resistivity become zero when the transition temperature Tc(offset) have 131 and 119 K, and the onset temperature Tc(onset) have 139 K for Hg0.8Sb0.2Ba2Ca2Cu3O8+δ and 132 K for Hg0.8Sb0.2Ba2Ca1Cu2O6+δ. Analysis of X-ray diffraction showed a tetragonal structure with lattice parameters changes for all samples.

Preparation of M2SiO4:Tb3+, Mn2+, Nd3+ White-Emitting Phosphors (M = Mg2+, Ca2+, Sr2+, and Ba2+) and the Influence of M2+ Cations on their Luminescent Performance

2021 ◽  
Vol 904 ◽  
pp. 329-333
Author(s):  
Qun Si Wang ◽  
Jun Feng Ma ◽  
Tian Qing Cui ◽  
Dong Bin Tang ◽  
Qi Zhou
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Solid State Reaction ◽  
Emission Intensity ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Near Ultraviolet ◽  
Violet Radiation ◽  
Luminescence Performance

M2SiO4: Tb3+, Mn2+, Nd3+ (M = Mg2+, Ca2+, Sr2+, and Ba2+) phosphors suitable for near-ultraviolet-violet radiation excitation were successfully prepared at 1400 °C in N2 atmosphere by a high-temperature solid-state reaction, and their phase compositions and luminescent performance were also studied by X-ray diffraction (XRD), photoluminescence spectra. Results show that their emission intensity increases in the order of Ca2SiO4 > Mg2SiO4 > Sr2SiO4 > Ba2SiO4 matrix phosphor. Ca1.94SiO4: 0.02Tb3 +, 0.02Mn2+, 0.02Nd2+ phosphor exhibits the best luminescence performance.

In-situ analysis of chemical expansion and stability of SOFC cathodes

2014 ◽  
Vol 1655 ◽  
Author(s):  
Mirela Dragan ◽  
Scott Misture
Keyword(s):  
High Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Lattice Parameter ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
Chemical Expansion ◽  
X Ray ◽  
Reducing Conditions ◽  
The Stability

ABSTRACTIn this work high-temperature X-ray diffraction has been used to investigate thermal and chemical expansion as well as overall phase stability for various cathode materials: Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF), La0.3Sr0.7CoO3 (LSC37), La0.6Sr0.4CoO3 (LSC64) and La0.6Sr0.4Fe0.8Co0.2O3 (LSCF), as a function of temperature in reducing conditions. When perovskites materials are under a low oxygen partial-pressure condition, the lattice parameter and overall dimension increase. Their chemical expansion has comparable values. From the viewpoint of the stability of these phases, the high-temperature X-ray diffraction results indicate no phase decomposition can be one of the reasons for material failure at the current experimental oxygen partial pressure. LSF is most stable, while LSC and LSCF form oxygen vacancy-ordered phases and then decompose when heated to 1000°C under atmospheres with pO2 as low as 10-5 atm.

Crystal structure and X-ray diffraction data of a new hexagonal perovskite compound, Ba4CuNb3O12

2011 ◽  
Vol 26 (3) ◽  
pp. 244-247
Author(s):  
N. Kumada ◽  
W. Zhang ◽  
Q. Dong ◽  
T. Mochizuki ◽  
Y. Yonesaki ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Chemical Composition ◽  
Solid State ◽  
Diffraction Data ◽  
Solid State Reaction ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Copper

A new barium copper niobate, Ba4CuNb3O12, was successfully prepared by high-temperature solid-state reaction in an inert atmosphere. Rietveld-refinement analysis of the XRD data of the compound showed that it has the 8H-type hexagonal perovskite structure with space group P63/mmc (#194), a = 5.830(1) Å, c = 19.123(1) Å, and chemical composition of Ba4Cu1.84Nb2.16O12-δ.

Phase relations in the Ba–Sr–Co–Fe–O system at 1273 K in air

2009 ◽  
Vol 42 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Zhèn Yáng ◽  
Ashley S. Harvey ◽  
Anna Infortuna ◽  
Ludwig J. Gauckler
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Solid State Reaction Method ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray

Selected compositions of the Ba–Sr–Co–Fe–O system were synthesized from powders by the solid-state reaction method. Samples were equilibrated at 1273 K for 36 000 s in air. The resulting powders were characterized by X-ray diffraction (XRD) at room temperature and by high-temperaturein situXRD. The phases present in the BaxSr1−xCoyFe1−yO3−δsystem are outlined for 1273 K in air. For most of the quaternary compositions, the cubic perovskite is formed, except for the compositions withx= 1 (excludingy= 0.4),y= 1 andx,y= 0.8, where the phases mainly show hexagonal distortions, andx, y= 0, for which a predominant cubic phase is mixed with other phases.

VARIATION OF Tc IN SINGLE PHASE Bi2Sr2Ca1Cu2O8−x SYSTEM

1991 ◽  
Vol 05 (24n25) ◽  
pp. 1645-1653
Author(s):  
M. NASIR KHAN ◽  
F.A. KHWAJA ◽  
RAANA FARID
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Electron Density ◽  
Solid State Reaction ◽  
Single Phase ◽  
High Temperature Superconductor ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Layer Spacing ◽  
X Ray

The variation of Tc in a single-phase high temperature superconductor Bi 2 Sr 2 Ca 1 Cu 2 O 8−x is studied using techniques like X-ray diffraction, magnetic and electric measurements. The samples of Bi-Sr-Ca-Cu-O (with nominal composition 2212) are synthesized by solid state reaction using appropriate amounts of Bi 2 O 3, SrCO 3, CaCO 3 and CuO powders. The Tc is found to vary from 92 K to 115 K in the quenched samples. These changes in the value of Tc have been related to the changes in the inter-layer spacing. It is concluded that an increase in the electron density due to shortening of the inter-layer increases the attractive interaction between pairs and is thus responsible for the high Tc in these superconductors.

Decrease in Resistance of Ceria Oxygen Sensor Induced by 10 mol% Hf and Zr Doping

2005 ◽  
Vol 888 ◽  
Author(s):  
Noriya Izu ◽  
Woosuck Shin ◽  
Ichiro Matsubara ◽  
Norimitsu Murayama
Keyword(s):  
Solid State ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Solid State Reaction ◽  
Pressure Range ◽  
Oxygen Sensor ◽  
Cubic Phase ◽  
Doped Ceria ◽  
Oxygen Gas ◽  
Resistive Type

ABSTRACTResistive type sensors using 10 mol% Hf-doped ceria and 10 mol% Zr-doped ceria, which had a single cubic phase obtained by solid state reaction, were fabricated and their sensing properties were investigated. The resistance and resistivity of the 10 mol% Hf-doped ceria or 10 mol% Zr-doped ceria were smaller than those of non-doped ceria. In the case of the same temperature of solid state reaction, the resistance and resistivity of the 10 mol% Hf-doped ceria were much smaller than those of the 10 mol% Zr-doped ceria. Furthermore, in the case of the same dopant, the resistance and resistivity of the sensor prepared from the solid state reaction at 1773 K were much smaller than those at 1673 K. The sensor using the 10 mol% Hf-doped ceria could be used as an oxygen gas sensor in wide oxygen partial pressure range and could be applicable to a λ sensor and a universal A/F sensor.

Preparation of Ultra–Fine La3NbO7 Powder by Solid State Reaction

2012 ◽  
Vol 512-515 ◽  
pp. 158-161 ◽  
Author(s):  
Ling Dai ◽  
Qiang Xu ◽  
Shi Zhen Zhu ◽  
Ling Liu
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Thermal Barrier ◽  
X Ray Diffraction ◽  
X Ray ◽  
Granular Particle ◽  
Fine Particle Size ◽  
Ultra Fine Particle ◽  
Different Temperatures

As a new candidate material for the ceramic layer in thermal barrier coatings (TBCs) system, La3NbO7 was synthesized with La2O3 powder and Nb2O5 powder by solid state reaction. The stating powders with a mole ratio of La to Nb of 3:1 were mixed and then the mixture was calcined under the different temperatures(800°C, 1000°C, 1200°C) and dwell times(2h, 6h, 10h). The phase structure of the powder was observed by X–ray diffraction(XRD), and the microstructure of the sample was observed by scanning electron microscope(SEM). The effect of calcination temperature and dwell Time on the phase formation were examined. The results indicate that the La3NbO7 powder with single phase can be synthesized successfully at 1200°C for 10h in air, and the La3NbOsub>7 powders synthesized have an ultra-fine particle size of 0.5˜1µm with a granular particle shape. With the temperature increasing, LaNbO4/sub> was synthesized firstly and then La3NbO7 was synthesized with a mole ratio of La2O3 to LaNbO4 of 1:1.

Niobium-bearing arsenides and germanides from elemental mixtures not involving niobium: a new twist to an old problem in solid-state synthesis

2018 ◽  
Vol 74 (5) ◽  
pp. 623-627 ◽  
Author(s):  
Sviatoslav Baranets ◽  
Hua He ◽  
Svilen Bobev
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Diffraction Data ◽  
Alkaline Earth ◽  
Alkaline Earth Metals ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Reactions ◽  
First Time ◽  
Synthetic Work

Three isostructural transition-metal arsenides and germanides, namely niobium nickel arsenide, Nb0.92(1)NiAs, niobium cobalt arsenide, NbCoAs, and niobium nickel germanide, NbNiGe, were obtained as inadvertent side products of high-temperature reactions in sealed niobium containers. In addition to reporting for the very first time the structures of the title compounds, refined from single-crystal X-ray diffraction data, this article also serves as a reminder that niobium containers may not be suitable for the synthesis of ternary arsenides and germanides by traditional high-temperature reactions. Synthetic work involving alkali or alkaline-earth metals, transition or early post-transition metals, and elements from groups 14 or 15 under such conditions may yield Nb-containing products, which at times could be the major products of such reactions.

Thermal enhancement of 2H11/2→4I15/2 up-conversion luminescence of Er3+ doped K2Yb(PO4)(MoO4) phosphors

2021 ◽  
Author(s):  
Hongqiang Cui ◽  
Yongze Cao ◽  
Lei Zhang ◽  
Yuhang Zhang ◽  
Siying Ran ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Reaction Method ◽  
X Ray ◽  
Thermal Enhancement

Er3+ with different concentrations doped K2Yb(PO4)(MoO4) phosphors were prepared by a solid-state reaction method, and the layered orthorhombic crystal structure of the samples was confirmed by X-ray diffraction (XRD). Under...

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