Electrochemical impedance study of platinum electrode in fused Na[sub 2]SO[sub 4]-10 mole percent NaVO[sub 3] melts

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2043853· OSTI ID:6537538

Zheng, X; Rapp, R A ^[1]

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1. Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

Sodium sulfate, the most common salt deposit involved in hot corrosion, results from the combustion of S-containing fuel in an NaCl-containing air. Another particularly harmful species in hot corrosion is vanadium, which may originate from low-grade V-containing fuels. During combustion of the low-grade fuel, Na[sub 2]SO[sub 4], V[sub 2]O[sub 5], and NaVO[sub 3] form as condensed phases which cause hot corrosion of the combustion equipment. An electrochemical impedance study was made for a platinum working electrode in Na[sub 2]SO[sub 4]-10 mole percent (m/o) NaVO[sub 3] melts in a temperature range of 1,150 to 1,200 K. The principal electroactive oxidant is a solute of V[sub 2]O[sub 5], which has a lower Warburg coefficient than that for the major oxidant S[sub 2]O[sub 7][sup 2[minus]] in pure Na[sub 2]SO[sub 4] melts in contact with 0.1 and 1%SO[sub 2]-O[sub 2] environments. The effects of temperature, basicity, oxygen potential, and polarization potential on the impedance of the system were investigated. The results are used to interpret hot corrosion induced by Na[sub 2]SO[sub 4]-NaVO[sub 3] deposits. In the vanadate-sulfate melt, the oxidant arrives at the electrode/electrolyte interface by the counterdiffusion of solutes with V[sup 4+] (V[sub 2]O[sub 4]-derived) and V[sup 5+] (V[sub 2]O[sub 5]-derived). Electron hopping in this solution does not occur.

• OSTI ID: 6537538
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 142:1; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKALI METAL COMPOUNDS
CALORIFIC VALUE
CHALCOGENIDES
CHEMICAL REACTIONS
COMBUSTION CHAMBERS
COMBUSTION PROPERTIES
CORROSION
CORROSIVE EFFECTS
ENGINES
FUELS
GAS TURBINE ENGINES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
OXIDES
OXIDIZERS
OXYGEN COMPOUNDS
PARAMETRIC ANALYSIS
REDOX REACTIONS
SODIUM COMPOUNDS
SODIUM SULFATES
SULFATES
SULFUR COMPOUNDS
SULFUR CONTENT
TRANSITION ELEMENT COMPOUNDS
VANADATES
VANADIUM COMPOUNDS
VANADIUM OXIDES