NIST High Temp. Superconducting Materials (HTS) Database:

NIST Standard Reference Database 62

Last Update to Data Content: 1996

DOI: https://doi.org/10.18434/T4KP8J


Bibliographic Information

Title: Formation of the 124-Phase Superconductor YBa2Cu4O8
Author(s): J. Niska, B.M. Andersson, B. Loberg, K. Easterling, and B. Sundqvist
Publication: Journal of Materials Science Letters Volume: 9 Issue: Not Available Year: 1990 Page(s): 770-771
Editor(s): Not Available
Publisher: Chapman and Hall
Language: English
Notes: Not Available
Keywords: Material Specification, Critical Temperature, Hardness

Materials and Properties

Y:124; [Y-Ba-Cu-O]
Material Specification for Y:124; [Y-Ba-Cu-O] Process: Hot Isostatic Pressing
Notes: "A powder sample of the superconducting 123 phase was blended with a stoichiometric ratio of CuO powder and loaded into a borosilicate glass tube. The tube was evacuated before sealing, to minimize residual gas porosity. The sample was hot isostatically pressed at about 1005 °C and 200 MPa using a hold time of 2 h. The HIP was slowly cooled to about 400 °C while retaining a high pressure to avoid decomposition of the material... The density of a polished cross-section was measured to be about 98.5% of full density by pore counting. The porosity was not uniform..."
Formula: YBa2Cu4O8
Informal Name: Y:124
Chemical Family: Y-Ba-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:

Critical Temperature for Y:124; [Y-Ba-Cu-O]
Critical Temperature (K)
70
Measurement Method: Electrical resistance
"The zero-resistance Tc (was determined)."

Cautions: Unevaluated Data
No measurement details were noted.
Hardness for Y:124; [Y-Ba-Cu-O]
Temperature (K) Hardness (GPa)
296 2.8
Measurement Method: Vickers indentation
The authors indicated that a Vickers microhardness tester was used with a load of 15 g applied by a diamond pyramid indenter. No additional measurement details were noted.

Cautions: Unevaluated Data
"The 124-phase material was found to be brittle, which leads to crushing and cracking along grain boundaries when microhardness testing (is performed) even with a 15 g load..."