The role of carbides in the corrosion behavior of FE-12Cr-1MoVW steel in liquid lithium

Conference · Wed Mar 01 04:00:00 EST 1989 · Fusion Technol.; (United States)

OSTI ID:6050047

Bell, G E; Abdou, M A

Experimental investigations with lithium and Fe-12Cr-1MoVW alloy in two thermal convection loops (360 to 505/sup 0/C and 530 to 655/sup 0/C) have shown that weight changes in these systems are not simple increasing functions of temperature. It was found that redistribution of carbon from the ..cap alpha..-ferrite phase of the isothermally annealed material by the formation of large (10 - 20 ..mu..m in diameter) surface carbides with the crystallographic structure of M/sub 23/C/sub 6/ (M = Fe or Cr) dominate the weight changes between 450 and 580/sup 0/C. The release of carbon from the surface ..cap alpha..-ferrite is probably due to decreased surface chromium activity by the formation of Li/sub 9/CrN/sub 5/ in the lower temperature experiment. In the higher temperature experiment, the difference in carbon activity between the steel and lithium is probably due to the rapidly increasing solubility of carbon in the lithium. The stoichiometry of the surface carbides varied from Cr/sub 18.8/Fe/sub 4.2/C/sub 6/ to Cr/sub 3.2/Fe/sub 19.8/C/sub 6/ with temperature and loop position, while surface substrate chromium content ranged from 4 to 8% by weight, decreasing with increasing temperature. Controlling initial chromium and carbon activities in the steel by decreasing carbon contents and/or by substituting more stable carbide-forming elements such as titanium or vanadium for chromium could help to mitigate the problem.

• Research Organization: UCLA, Los Angeles, CA (US)
• OSTI ID: 6050047
• Report Number(s): CONF-881031-
• Conference Information: Journal Name: Fusion Technol.; (United States) Journal Volume: 15:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360104 -- Metals & Alloys-- Physical Properties
360105* -- Metals & Alloys-- Corrosion & Erosion
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALI METAL COMPOUNDS
ALLOYS
CARBIDES
CARBON ADDITIONS
CARBON COMPOUNDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COOLANT LOOPS
COOLING SYSTEMS
CORROSION
DATA
ELEMENTS
ENERGY SYSTEMS
EXPERIMENTAL DATA
FERRITE
HIGH TEMPERATURE
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
ISOTHERMAL PROCESSES
KINETICS
LITHIUM CARBIDES
LITHIUM COMPOUNDS
LOW TEMPERATURE
MATERIALS TESTING
METALS
MOLYBDENUM ALLOYS
NUMERICAL DATA
REACTION KINETICS
STEELS
STOICHIOMETRY
TEMPERATURE EFFECTS
TESTING
THERMAL CYCLING
TITANIUM
TRANSITION ELEMENTS
TUNGSTEN ALLOYS
VANADIUM ALLOYS