Elimination of Oxygenation Cracking in YBCO Bulk Superconductors

2009 ◽  
Vol 409 ◽  
pp. 216-222
Author(s):  
Pavel Diko ◽  
Xavier Chaud ◽  
Vitaliy Antal ◽  
Mária Kaňuchová ◽  
Martina Šefčíková ◽  
...  
Keyword(s):  
Lattice Parameters ◽  
Oxygen Stoichiometry ◽  
Low Oxygen ◽  
Ybco Bulk ◽  
Oxygen Penetration ◽  
Thermal Expansion Coefficients ◽  
Bulk Superconductors ◽  
Single Grain ◽  
Expansion Coefficients ◽  
Crystal Lattice Parameters

The reasons for cracking of YBa2Cu3Oδ/Y2BaCuO5 (Y123/Y211 or YBCO) bulk single-grain superconductors are mechanical stresses, which arise in the sample during its fabrication. Two main sources of stresses appearing during fabrication were identified: the different thermal expansion coefficients of 123 and 211 phases and the dependence of 123 phase lattice parameters on the oxygen stoichiometry. As-grown YBCO bulks have low oxygen content, YBa2Cu3O6.3, are not superconducting, and must be oxygenated to form YBa2Cu3O7. During standard oxygenation at 400 °C the shortening of crystal lattice parameters causes intensive cracking. The created cracks allow oxygen penetration into the bulk and cause the oxygenation time to be technologically acceptable but reduce significantly the superconducting properties. Here we show that it is possible to eliminate the formation of oxygenation cracks and to reach a critical current density 2.5 times higher than in material bulk oxygenated in a standard way. The oxygenated crack-free samples were obtained by high pressure oxygenation with progressively increasing oxygen partial pressure.

Experience of Using Complex Modifiers to Increase Corrosion Resistance of Pipe Steels

2021 ◽  
Vol 316 ◽  
pp. 369-374
Author(s):  
Aleksey N. Shapovalov ◽  
Roman R. Dema ◽  
Sergey P. Nefed'ev
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth Metals ◽  
Test Results ◽  
Pipe Steels ◽  
Low Oxygen ◽  
Thermal Expansion Coefficients ◽  
Barium Strontium ◽  
Metallic Inclusions ◽  
Expansion Coefficients ◽  
Increase Corrosion Resistance

The article presents the test results of complex microcrystalline modifiers containing calcium, barium, strontium, rare earth metals. Complex modifiers were used in the processing of steel for 17G1S-U pipes in order to reduce its contamination with non-metallic inclusions, including corrosive ones. The use of modifiers allowed to reduce metal contamination by non-metallic inclusions of all kinds. The most experimental non-metallic inclusions were obtained during metal processing with INSTEEL®5.1 and INSTEEL®9.4 modifiers. In addition, the use of experienced modifiers ensured the production of complex oxysulfides of calcium, cerium and lanthanum with low oxygen content and thermal expansion coefficients, which increases the corrosion resistance of steel.

Assessment of phase transition and thermal expansion coefficients by means of secondary multiple reflections of Renninger scans

2019 ◽  
Vol 52 (6) ◽  
pp. 1271-1279
Author(s):  
Adenilson O. dos Santos ◽  
Rossano Lang ◽  
José M. Sasaki ◽  
Lisandro P. Cardoso
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Structural Phase ◽  
Angular Position ◽  
Lattice Parameters ◽  
Rochelle Salt ◽  
Multiple Reflections ◽  
Multiple Diffraction ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

This paper reports the successful extension of the basis of the X-ray multiple diffraction phenomenon in the assessment of structural phase transitions and the determination of thermal expansion coefficients along three crystallographic directions, using synchrotron radiation Renninger scans. Suitable simultaneous four-beam cases have accurately resolved the lattice-parameter variation in a nearly perfect single-crystal Rochelle salt using a high-stability temperature apparatus. Secondary reflections observed in the Renninger patterns, chosen by their sensitivity to the shifts in angular position as a function of temperature, have allowed the detection of a monoclinic to orthorhombic phase transition, as well as subtle expansions of all the basic lattice parameters, i.e. without having to carry out measurements on each crystal axis. The thermal expansion coefficients have been estimated from the linear fit of the temperature dependence of the lattice parameters, and are in agreement with those reported in the literature.

Optimum processing conditions for the fabrication of large, single grain Ag-doped YBCO bulk superconductors

2008 ◽  
Vol 151 (1) ◽  
pp. 2-6 ◽  
Author(s):  
K. Iida ◽  
N.H. Babu ◽  
S. Pathak ◽  
Y. Shi ◽  
W.K. Yeoh ◽  
...  
Keyword(s):  
Processing Conditions ◽  
Ybco Bulk ◽  
Optimum Processing ◽  
Bulk Superconductors ◽  
Single Grain

An X-ray determination of the thermal expansion of α-phase Cu–Si alloys at high temperature

1989 ◽  
Vol 22 (4) ◽  
pp. 380-381
Author(s):  
S. K. Pradhan ◽  
M. De
Keyword(s):  
Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Solute Concentration ◽  
Lattice Parameters ◽  
Thermal Expansion Coefficients ◽  
Solid Solution Range ◽  
Expansion Coefficients ◽  
Increasing Temperature ◽  
Room Temperature Increase

Lattice parameters for four Cu–Si alloys containing 2.2, 4.3, 6.4 and 8.7 at.% Si in the solid-solution range have been calculated in the temperature range 303–928 K. The lattice parameters increase slowly in a nonlinear manner with rise in temperature. The calculated linear thermal-expansion coefficients (α) at room temperature increase with increasing solute concentration (Si) but decrease almost linearly with increasing temperature, the rate of decrease being higher for alloys with higher solute concentration. All the alloys have almost the same average α value (α av ~ 16.0 × 10−6 K−1), which is the value of α at the temperature interval 615–625 K for all the alloy compositions.

Study of lattice parameters and thermal expansion coefficients on Bi1.7Pb0.3Sr2Ca2Cu3O10

1994 ◽  
Vol 143 (1) ◽  
pp. 117-121 ◽  
Author(s):  
S. O. Chen ◽  
H. M. Shen ◽  
L. S. Bai ◽  
Y. N. Wang
Keyword(s):  
Thermal Expansion ◽  
Lattice Parameters ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients
Sign in / Sign up

Export Citation Format

Share Document