Accession Number : AD0728825

Title :   Effect of Applied Electric Fields on the Mechanisms of Oxidation of Metals and Alloys.

Descriptive Note : Final rept. 15 Apr 70-15 Apr 71,

Corporate Author : LITTLE (ARTHUR D) INC CAMBRIDGE MASS

Personal Author(s) : Berkowitz-Mattuck,Joan B. ; Ketteringham,John M. ; Menashi,Wilson P.

Report Date : 15 APR 1971

Pagination or Media Count : 43

Abstract : An exploratory study was made of the effects of applied electrical potentials on the oxidation/hot corrosion behavior of Nichrome, nickel, and Kanthal in seeded propane/air flames. Temperatures were maintained at about 1200C. Typical seed materials, vaporized into the flame from a nickel crucible, included K2CO3, K2SO4, and Na2CO3. The alkali metal ions were used to increase the conductivity of the flame; K2SO4 served as a source of sulfur as well. In several experiments SO2(g) was introduced separately from the alkali metal seed. In one series of experiments, Nichrome samples were coated with sodium sulfate salt and tested in unseeded flames. Sheet samples were polarized at voltages of -300 to +300 V with respect to various counter electrodes. In all the experiments on nickel based samples, it was found that negative polarization (sample cathodic) drastically accelerated scaling reactions and often altered scale morphology, leading to deep grain boundary penetration of corrosion products. When the samples were polarized anodically, the reaction rate was visibly lower than observed cirucit potential. (Author)

Descriptors :   (*CORROSION, ELECTRIC FIELDS), REACTION KINETICS, OXIDATION, NICKEL, NICKEL ALLOYS, FLAMES

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE