Accession Number : ADA190699

Title :   High Temperature Oxidation and Electrochemical Studies Related to Hot Corrosion.

Descriptive Note : Annual technical rept.,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEE RING

Personal Author(s) : Kim, D-H ; Patton, J ; Simkovich, G

PDF Url : ADA190699

Report Date : Dec 1987

Pagination or Media Count : 26

Abstract : This report covers some of the results attained during the last year concerning attempts to elucidating the mechanisms(s) at hot corrosion processes. AC impedance tests and Wagner-Hebb type polarization measurements on pure Na2SO4 at 900 C were performed as a function of Na2O activities. These results, to be published in an Electrochem. Soc. Proceedings showed that the conductivties of the pure Na2SO4 were of the order of .257/ohm-cm and varied only slightly with Na2O activity changes. From the Wagner-Hebb type polarization measurements on the pure Na2SO4 it was found that electron conductivity was much higher than electron hole conductivity. Additional tests were conducted to determine (1) the effect of height of Na2SO4 melts, (2) the effect of electronic short circuiting the Na2SO4 melts with gold wires and (3) the effect of presaturating the salt melt with corrosion products in the hot corrosion process. However, the amount of Na2SO4 present, which is directly proportional to the height of the melt, does affect the rate of corrosion. This was demonstrated by the decrease in rate observed when the melt was pre-saturated with the corrosion products.

Descriptors :   *CORROSION, *ELECTROCHEMISTRY, *OXIDATION, *SODIUM SULFATES, *SUPERALLOYS, CONDUCTIVITY, ELECTRONS, GOLD, HIGH TEMPERATURE, MELTS, RATES, SALTS, WIRE, REACTION KINETICS, NICKEL ALLOYS, CHROMIUM ALLOYS

Subject Categories : Physical Chemistry
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE