The effect of preoxidation on the sulfidation of Ni-20Cr (2-5)Al alloys. 1. Effect of preoxidation on scale characteristics and sulfidation at 750C

Journal Article · Sun Dec 01 00:00:00 EST 1991 · Oxidation of Metals; (United States)

DOI:https://doi.org/10.1007/BF01151587· OSTI ID:5404060

Ohla, K; Kim, S W; Fischmeister, H; Fromm, E ^[1]

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1. Max-Planck Fuer Metallorschung, Stuttgart (West Germany)

Ni-20Cr alloys with 2, 3.5, and 5 wt% Al have been preoxidized up to 100 hr at 1,000C in dry H{sub 2}, in H{sub 2}/23% H{sub 2}O an in air and subsequently exposed to an H{sub 2}/5% H{sub 2}S atmosphere at 750C. During the preoxidation treatment different types of oxide scales were formed which affect the sulfidation protection in different ways. Optimum results were obtained for alloys with 3.5 and 5 wt% Al after 20 hr exposure to dry H{sub 2} at 1,000C. A thin Al{sub 2}O{sub 3} scale is formed which decreases the sulfur attack by more than one order of magnitude. Preoxidation conditions for Ni-20Cr-2Al alloys in H{sub 2} and for Ni-20Cr-2Al and Ni-20Cr-3.5 Al in H{sub 2}/H{sub 2}O were observed to be less effective. No improvement was found for preoxidation in air or for Ni-20Cr-5 Al alloys preoxidized in H{sub 2}/H{sub 2}O.

• OSTI ID: 5404060
• Journal Information: Oxidation of Metals; (United States), Vol. 36:5-6; ISSN 0030-770X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
OXIDATION
PROTECTIVE COATINGS
SULFIDATION
CHROMIUM ALLOYS
NICKEL BASE ALLOYS
AIR
ALUMINIUM OXIDES
AUGER ELECTRON SPECTROSCOPY
CORROSION RESISTANCE
EXPERIMENTAL DATA
HYDROGEN
HYDROGEN SULFIDES
LAYERS
MORPHOLOGY
SCALING
SCANNING ELECTRON MICROSCOPY
TEMPERATURE RANGE 1000-4000 K
WATER VAPOR
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
ALLOYS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
COATINGS
COHERENT SCATTERING
DATA
DIFFRACTION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
FLUIDS
GASES
HYDROGEN COMPOUNDS
INFORMATION
MICROSCOPY
NICKEL ALLOYS
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
SCATTERING
SPECTROSCOPY
SULFIDES
SULFUR COMPOUNDS
TEMPERATURE RANGE
VAPORS
360105* - Metals & Alloys- Corrosion & Erosion