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Łada T. Przybylski K. Morawski A. Prażuch J. Brylewski T. 《Journal of Thermal Analysis and Calorimetry》2001,64(2):611-615
The fabrication method of superconducting thin films of compositions HgBa2Ca2Cu3O8+δ (Hg-1223) and Tl2Ba2CuOy (2201) on single-crystalline SrTiO3 and LaAlO3 substrates is reported. The highest obtained T
c was 134 K and J
c over 106 A cm–2 at 77 K. High pressure DTA(HP-DTA) was applied to grow mercury- and thallium-based high-temperature superconducting crystals
and thin films, to identify melting points of particular phases within these oxide systems and determine suitable processing
conditions. The DTA system operates at the: maximum temperature of 1200°C, volume up to 5 cm3, working pressure up to 1.5 GPa and at a working atmosphere — inert gas with up to 25% oxygen.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
K. Przybylski T. Brylewski M. Bućko 《Journal of Thermal Analysis and Calorimetry》1995,45(5):1099-1108
Calcination conditions of the precursor powders, i.e. temperature, type of atmosphere and duration, were determined with a view to obtain superconducting powders with the most advantageous physico-chemical properties. Investigated were powders in the Y?Ba?Cu?O system prepared by the sol-gel method. Thermogravimetric examinations of the powders have revealed that the decomposition kinetics of BaCO3 determines the formation rate of the superconducting YBa2Cu3O7?x (‘123’) phase. It follows from the decomposition kinetics of BaCO3 that the process is the most intensive in argon, whereas in static air and oxygen it is the slowest. The phase composition analysis (XRD) and low-temperature magnetic susceptibility measurements of the calcinated powders, confirm the above mentioned changes in the decomposition kinetics. The reaction of barium carbonate can be completed if the calcination process is conducted at the temperature of 850°C for 25 h, yielding easily sinterable powders for obtaining single-phase superconducting bulk samples with advantageous functional parameters. 相似文献
3.
Kinetics of oxidation of Fe-Cr steel containing 25 wt.-percent Cr was studied as a function of temperature (1023–1173 K) for
up to 480 h in flowing air, which corresponds to SOFC cathode environment operating conditions. The oxidation process was
found to be a parabolic, suggesting that the diffusion of ionic defects in the scale is the slowest, rate determining step
and it occurs predominantly by short-circuit diffusion paths. Comparison of the determined activation energy of oxidation
of the studied steel with literature data indicates that at 1098–1173 K the chromia scale grows by the outward solid-state
diffusion of chromium interstitials, whereas at 1023–1098 K — through a significant contribution of counter-current oxygen/chromium
diffusion along Cr2O3 grain boundaries. The oxide scales were composed mainly of Cr2O3 with a continuous thin Mn1.5Cr1.5O4 spinel layer on top of the chromia scale. The oxidation test results on Fe-25Cr steel demonstrate the applicability of the
commercial type DIN 50049 stainless steel as interconnect for SOFC.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
The crystallization mechanism of superconducting phases in the (Bi,Pb)?Sr?Ca?Cu?O system was determined on the basis of the results of DTA, DTG and TG studies, supplemented by X-ray examination of ceramic powders obtained by the sol-gel method. It has been demonstrated that the factor determining the formation of superconducting phases: Bi2Sr2CaCu2Ox (low-T c ) and Bi2Sr2Ca2Cu3Ox (high-T c ) is the kinetics of reaction of calcium and strontium carbonates with molten CuBi2O4. As a result of the reaction of the bimetallic compound CuBi2O4 with SrCO3 in the liquid phase the compound Bi2Sr2CuO6 is formed. This compound, reacting with calcium and copper oxides, yields superconducting phases: the low-T c and the high-T c phase. It has been also observed that an increase in the volume fraction of high-T c phase in powder subjected to thermal treatment takes place probably due to the repeated disproportionation of low-T c phase and its repeated synthesis from Bi2Sr2CuO6, CuO and CaO. 相似文献
5.
Andrzej Kruk Miroslaw Stygar Tomasz Brylewski 《Journal of Solid State Electrochemistry》2013,17(4):993-1003
This paper presents research on the synthesis and properties of the Mn1.5Co1.5O4 (MC) spinel powder, as well as its application for the preparation of a MC thick film on the AL453 steel to be used for metallic interconnect material in IT-SOFCs. In order to prepare the MC micropowder with excellent homogeneity of the chemical and phase compositions, EDTA gel processes were utilized. In order to improve the contact electrical resistance between an AL453 steel interconnect and the La0.8Sr0.2FeO3 (LSF) cathode and protect the cathode from Cr poisoning, the surface of the AL453 steel was coated with a protective manganese cobaltite spinel matrix using screen printing in combination with an appropriate heat treatment. The oxidation of the AL453/MC composite layer carried out in the air–H2O gas mixture at 1,073 K for 55 h showed that the spinel coating may serve as an effective barrier against outward Cr diffusion from the AL453 steel and, therefore, significantly inhibit the formation of volatile Cr vapors from the chromia scale. The contact ASR study of the interconnect–cathode interface in the AL453/MC/LSCM/LSF/LSCM/MC/AL453 system carried out in the range of 723?1,073 K in air showed a very large drop in ASR compared to the resistance of the AL453/LSCM/LSF/LSCM/AL453 system without the spinel coating. 相似文献
6.
Mazur Łukasz Molin Sebastian Dąbek Jarosław Durczak Karol Pyzalski Michał Brylewski Tomasz 《Journal of Thermal Analysis and Calorimetry》2022,147(10):5649-5666
Journal of Thermal Analysis and Calorimetry - The Crofer 22 H ferritic steel substrate was coated with an Mn1.45Co1.45Cu0.1O4 spinel by means of electrophoresis. After high-temperature oxidation... 相似文献
7.
Przybylski K. Brylewski T. Morawski A. Łada T. 《Journal of Thermal Analysis and Calorimetry》2001,65(2):391-398
The influence of Ba2Ca2Cu3Ox precursor on the synthesis and properties of (Hg,Pb)Ba2Ca2Cu3O8+δ has been examined. Fine homogeneous Hg-free precursor powder of Ba2Ca2Cu3Ox of desirable phase composition was prepared by sol-gel method using EDTA acid as a complexing agent. A reproducible superconducting
sample of Hg0.8Pb0.2Ba2Ca2Cu3O8+δ with fine-grained, dense microstructure, composed predominantly of (Hg,Pb)-1223 phase and with advantageous magnetic properties,
was synthesized by high pressure crystallization in mercury environment of well-calcined Ba2Ca2Cu3Ox precursor.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Brylewski T. Maruyama T. Nanko M. Przybylski K. 《Journal of Thermal Analysis and Calorimetry》1999,56(2):681-690
The high-temperature oxidation behavior of a ferritic alloy (SUS 430) in a SOFC environment, corresponding to the anode (H2/H2O gas mixture) and cathode (air) operating conditions, was determined with regard to application of the alloy as a metallic
separator material in SOFC. The oxidation kinetics of Fe-16Cr alloy (SUS 430), was studied by thermogravimetry in H2/H2O gas mixtures with pH/pHO=94/6 and 97/3 and in air, in the temperature range 1023-1223 K, for 3.6 up to 1080 ks. It was found that the protective oxide
scale, composed mainly of Cr2O3 with uniform thickness and excellent adhesion to the metal substrate, grows in accordance with the parabolic rate law. The
dependence of the parabolic rate constant, kp, of the scale on temperature obeys the Arrhenius equation: kp=6.8×10-4 exp (-202.3 kJ mol-1R-1T-1) for H2/H2O gas mixtures with pH/pHO=94/6. The determined kp was independent of the oxygen partial pressure in the range from 5.2×10-22 to 0.21 atm at 1073 K, which means that the rates of growth of the scale on Fe-16Cr alloy in the above-mentioned atmospheres
are comparable. The oxidation test results on Fe-16Cr alloy in H2/H2O gas mixtures and air demonstrate the applicability of SUS 430 alloys as a separator for SOFC.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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