Development of Nb/sub 3/Ge for power transmission applications. Final report

Technical Report · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6414276

Maley, M P; Newkirk, L R; Thompson, J D; Valencia, F A

Since its discovery in 1973 as the superconductor with the highest known transition temperature (T/sub c greater than or equal to 23/sup 0/K), Nb/sub 3/Ge has offered the possibility of operating temperatures greater than or equal to 14/sup 0/K, for superconducting devices. For application to the transmission of electric power, higher operating etmperatures imply increased efficiency and lower capital costs. However, in order for a superconducting material to be practical for power transmission, it must exhibit high critical current density, J/sub c/ greater than or equal to 10/sup 6/ A/cm/sup 2/, and low ac losses, < 10 ..mu..W/cm/sup 2/, at the operating temperature and current amplitude. In the initial phase of this program, completed in June 1976, the achievement of material properties in short samples (approx. 23-cm long) of Nb/sub 3/Ge that met the requirements for power transmission at T = 12.0/sup 0/K was reported. The material was produced by the chemical vapor deposition (CVD) process. In this report, the successful effort to develop a CVD process by which long lengths of Nb/sub 3/Ge-clad tapes can be produced with material properties matching those of the best short samples is described. This effort culminated in the production of a 20-m-long Nb/sub 3/Ge-clad tape. The tape consisted of a 0.65-cm-wide x 25-..mu..m-thick copper substrate, coated uniformly with a 4.0 ..mu..m-thick layer of Nb/sub 3/Ge. Sections taken from either end of the tape had measured values for J/sub c/ for 2.5 and 2.4 x 10/sup 6/ A/cm/sup 2/ at 13.8 K and material properties that varied by less than 5%. No limitations in the process have been detected for lengths up to 20 m, and scaling up to longer lengths should be reasonably straght-forward. The results of a parallel effort in optimizing Nb/sub 3/Ge for high critical currents at high temperatures and in material characterization are also described.

• Research Organization: Los Alamos Scientific Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6414276
• Report Number(s): EPRI-EL-965
• Country of Publication: United States
• Language: English

Related Subjects

200303* -- Power Transmission &amp; Distribution-- Superconducting &amp; Cryogenic Systems-- (-1989)
24 POWER TRANSMISSION AND DISTRIBUTION
AC LOSSES
AC SYSTEMS
ALLOYS
CABLES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
CONDUCTOR DEVICES
COPPER
CURRENT DENSITY
DATA
DATA FORMS
DEPOSITION
ELECTRIC CABLES
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELEMENTS
EQUIPMENT
EXPERIMENTAL DATA
FABRICATION
GERMANIUM ALLOYS
GRAPHS
INFORMATION
MECHANICAL PROPERTIES
METALS
NIOBIUM ALLOYS
NUMERICAL DATA
PHYSICAL PROPERTIES
POWER SYSTEMS
POWER TRANSMISSION LINES
SUPERCONDUCTING CABLES
SURFACE COATING
TABLES
TRANSITION ELEMENTS