Sodium sulfate-induced corrosion of pure nickel and a commercial nickel-base superalloy, Udimet(1) 700 (U-700), were studied at 900 C in a Mach 0.3 burner rig with different Na levels in the combustor. The corrosion rate of Ni was independent of the Na level in the combustor and considerably lower than that measured in laboratory salt spray tests. The lower rates are associated with the deposition of only a small amount of Na2SO4 on the surface of the NiO scale. Corrosion of U-700 was observed to occur in two stages. During the first stage, the corrosion proceeds by reaction of Cr2O3 scale with the Na2SO4 and evaporation of the Na2CrO4 reaction product from the surface of the corroding sample. Cr depletion in the alloy occurs and small sulfide particles are formed in the Cr depletion zone. Extensive sulfidation occurs during the second stage of corrosion, and a thick scale forms. The relationship between the corrosion rate of U-700 and the Na level in the combustor gives a good correlation in the range of 0.3 to 1.5 parts per million by weight (wppm) Na. Very low levels of Na in the combustor cause accelerated oxidation of U-700 without producing the typical hot corrosion morphology.
Skip Nav Destination
Article navigation
July 1987
Research Article|
July 01 1987
Sodium Sulfate-Induced Corrosion of Pure Nickel and Superalloy Udimet 700 in a High Velocity Burner Rig at 900 C
A. K. Misra
A. K. Misra
*Department of Metallurgy and Materials Science, Case Western Reserve University, Cleveland, Ohio 44106, and Resident Scientist, National Aeronautics and Space Administration, Lewis Research Center, Cleveland, Ohio 44135.
Search for other works by this author on:
Online ISSN: 1938-159X
Print ISSN: 0010-9312
National Association of Corrosion Engineers
1987
CORROSION (1987) 43 (7): 440–450.
Citation
A. K. Misra; Sodium Sulfate-Induced Corrosion of Pure Nickel and Superalloy Udimet 700 in a High Velocity Burner Rig at 900 C. CORROSION 1 July 1987; 43 (7): 440–450. https://doi.org/10.5006/1.3583882
Download citation file:
Citing articles via
Suggested Reading
Corrosion of Unstressed Superalloys by Molten Boron Oxide
CORROSION (June,1965)
An Evaluation of an Overlay Coated ODS Superalloy in High Temperature Oxidation and Burner Rig Environments
CONF_APR1989
Oxidation and Hot Corrosion of Some Advanced Superalloys at 1300 to 2000°F (704 to 1093°C)
CORROSION (August,1989)