High Temperature Oxidation and Electrochemical Studies Related to Hot Corrosion
Abstract
To aid in understanding hot corrosion processes, investigations of the electrical behavior of molten Sodium sulfate have been undertaken. Wagner- Hebb type polarization experiments and total electrical conductivity measurements by an A.C. impedance technique were carried out on melts of Na2SO4, both pure and those containing .001 m/o, .18 m/o, and supersaturated (10 m/o) Nickel oxide, as a function of Sodium monoxide activity at 1173 K. The relative contributions of cation versus anion transport in the molten sodium sulfate was investigated by employing a potentiostatic polarization technique. It was observed that the total electrical conductivity of pure Na2SO4 was of the order of .257 (ohm/cm) and varied only slightly with changes in the activity of Na2O. From the Wagner-Hebb type D.C. polarization experiments on pure Na2SO4, the electron conductivity was shown to be much greater than the electron hole conductivity over the entire range of Na2O activities. The partial conductivity of electrons in Na2SO4 was about three orders of magnitude less than the total electrical conductivity. The introduction of NiO into Na2SO4 melts at 1173 K did not produce massive changes in the total electrical conductivities of these melts as compared to those of a pure Na2SO4 melt. The addition of NiO in the melt decreases the electronic conductivities as well as the transport numbers of electronic species, regardless of the concentrations of NiO in the melt at 1173 K. Keywords: Alloys Oxidation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA203038
Entities
People
- D.-h. Kim
- G. Simkovich
- R. F. Reidy
Organizations
- Pennsylvania State University