The high-temperature corrosion of Fe-Nb alloys in a H sub 2 /H sub 2 O/H sub 2 S gas mixture

Journal Article · Wed Apr 01 04:00:00 EST 1992 · Oxidation of Metals; (United States)

DOI:https://doi.org/10.1007/BF00665189· OSTI ID:7266941

Kai, W; Douglass, D L ^[1]; Gesmundo, F ^[2]

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1. Univ. of California, Los Angeles (United States)
2. Univ. di Genova (Italy)

The corrosion of Fe-Nb alloys containing up to 40 wt.% Nb has been studied over the temperature range 600-980 C. in a mixed gas of constant composition having sulfur and oxygen pressures ranging from 10{sup {minus}8} to 10{sup {minus}4} atm. and from 10{sup {minus}27} to 10{sup {minus}18} atm., respectively. All alloys were two-phase, consisting of an Fe-rich solid solution and an intermetallic compound, Fe{sub 2}Nb. The scales formed on the Fe-Nb alloys were duplex, consisting of an outer layer of iron sulfide (FeS) and an inner complex layer of Fe{sub x}NbS{sub 2}(FeNb{sub 2}S{sub 4} or FeNb{sub 3}S{sub 6}), FeS and unreacted Fe{sub 2}Nb. No oxides were detected at any temperature. The addition of Nb reduced the corrosion rate. The corrosion kinetics of Fe-Nb alloys followed the parabolic rate law, regardless of alloy composition and temperature. Platinum markers, attached to the original alloy surfaces, were always located at the interface between, the inner and outer scales.

• OSTI ID: 7266941
• Journal Information: Oxidation of Metals; (United States), Journal Name: Oxidation of Metals; (United States) Vol. 37:3-4; ISSN 0030-770X; ISSN OXMEA
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ACTIVATION ENERGY
ALLOYS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL GASIFICATION PLANTS
CORROSION
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
DATA
DIAGRAMS
DISPERSIONS
ELEMENTS
ENERGY
EXPERIMENTAL DATA
FLUIDS
GASES
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
INDUSTRIAL PLANTS
INFORMATION
INTERMETALLIC COMPOUNDS
IRON ALLOYS
IRON BASE ALLOYS
IRON COMPOUNDS
IRON SULFIDES
KINETICS
MICROSCOPY
MIXTURES
NIOBIUM ALLOYS
NIOBIUM COMPOUNDS
NIOBIUM SULFIDES
NONMETALS
NUMERICAL DATA
OPTICAL MICROSCOPY
OXIDATION
OXYGEN
PARTIAL PRESSURE
PETROLEUM REFINERIES
PHASE DIAGRAMS
REACTION KINETICS
REFRACTORY METAL COMPOUNDS
SOLID SOLUTIONS
SOLUTIONS
SULFIDATION
SULFIDES
SULFUR COMPOUNDS
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
TEST FACILITIES
TRANSITION ELEMENT COMPOUNDS
VAPORS
WATER VAPOR
WEIGHT