Method of manufacture of single phase ceramic superconductors
Abstract
A ceramic superconductor is produced by close control of oxygen partial pressure during sintering of the material. The resulting microstructure of YBa{sub 2}Cu{sub 3}O{sub x} indicates that sintering kinetics are enhanced at reduced p(O{sub 2}) and that because of second phase precipitates, grain growth is prevented. The density of specimens sintered at 910 C increased from 79 to 94% theoretical when p(O{sub 2}) was decreased from 0.1 to 0.0001 MPa. The increase in density with decrease in p(O{sub 2}) derives from enhanced sintering kinetics, due to increased defect concentration and decreased activation energy of the rate-controlling species undergoing diffusion. Sintering at 910 C resulted in a fine-grain microstructure, with an average grain size of about 4 {mu}m. Post sintering annealing in a region of stability for the desired phase converts the second phases and limits grain growth. The method of pinning grain boundaries by small scale decompositive products and then annealing to convert its product to the desired phase can be used for other complex asides. Such a microstructure results in reduced microcracking, strengths as high as 230 MPa and high critical current density capacity. 25 figures.
- Inventors:
- Issue Date:
- Research Org.:
- Univ. of Chicago, IL (United States)
- OSTI Identifier:
- 35077
- Patent Number(s):
- 5401712
- Application Number:
- PAN: 7-947,324
- Assignee:
- Univ. of Chicago, IL (United States)
- DOE Contract Number:
- W-31109-ENG-38
- Resource Type:
- Patent
- Resource Relation:
- Other Information: PBD: 28 Mar 1995
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; HIGH-TC SUPERCONDUCTORS; SINTERING; MICROSTRUCTURE; YTTRIUM OXIDES; BARIUM OXIDES; COPPER OXIDES; CONTROLLED ATMOSPHERES
Citation Formats
Singh, J P, Poeppel, R B, Goretta, K C, and Chen, N. Method of manufacture of single phase ceramic superconductors. United States: N. p., 1995.
Web.
Singh, J P, Poeppel, R B, Goretta, K C, & Chen, N. Method of manufacture of single phase ceramic superconductors. United States.
Singh, J P, Poeppel, R B, Goretta, K C, and Chen, N. Tue .
"Method of manufacture of single phase ceramic superconductors". United States.
@article{osti_35077,
title = {Method of manufacture of single phase ceramic superconductors},
author = {Singh, J P and Poeppel, R B and Goretta, K C and Chen, N},
abstractNote = {A ceramic superconductor is produced by close control of oxygen partial pressure during sintering of the material. The resulting microstructure of YBa{sub 2}Cu{sub 3}O{sub x} indicates that sintering kinetics are enhanced at reduced p(O{sub 2}) and that because of second phase precipitates, grain growth is prevented. The density of specimens sintered at 910 C increased from 79 to 94% theoretical when p(O{sub 2}) was decreased from 0.1 to 0.0001 MPa. The increase in density with decrease in p(O{sub 2}) derives from enhanced sintering kinetics, due to increased defect concentration and decreased activation energy of the rate-controlling species undergoing diffusion. Sintering at 910 C resulted in a fine-grain microstructure, with an average grain size of about 4 {mu}m. Post sintering annealing in a region of stability for the desired phase converts the second phases and limits grain growth. The method of pinning grain boundaries by small scale decompositive products and then annealing to convert its product to the desired phase can be used for other complex asides. Such a microstructure results in reduced microcracking, strengths as high as 230 MPa and high critical current density capacity. 25 figures.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Mar 28 00:00:00 EST 1995},
month = {Tue Mar 28 00:00:00 EST 1995}
}