Accession Number : AD0707023

Title :   LOW TEMPERATURE OXIDATION (24 TO 200 C) AND KRYPTON ADSORPTION STUDIES ON POLYCRYSTALLINE AND SINGLE CRYSTAL IRON SURFACES,

Corporate Author : NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) DIV OF CHEMISTRY

Personal Author(s) : Graham,M. J. ; Ali,S. I. ; Cohen,M.

Report Date : 19 DEC 1969

Pagination or Media Count : 5

Abstract : Rates of oxidation of polycrystalline, (110), and (112) surfaces of iron have been measured at 24, 100, and 200C by a manometric method using an initial oxygen pressure of about 0.013 Torr. At the lower temperatures the relative rates of oxidation are found to be polycrystalline, (110), and (112) in decreasing order. At 200C the different single crystal surfaces oxidize at essentially the same rate. Logarithmic rate laws are obeyed reasonably well for oxidations up to 200C, at which point the oxidation rate, after a time, obeys a parabolic law. Using this parabolic rate constant for the oxidation of polycrystalline iron at 200C, together with previous microbalance data for the low pressure oxidation of iron at 350 and 400C (1), an activation energy of 32 kcal./mole is found for the formation of magnetite on iron. (Author)

Descriptors :   (*IRON, *SURFACE PROPERTIES), (*OXIDATION, IRON), ADSORPTION, KRYPTON, SINGLE CRYSTALS, SURFACES

Subject Categories : Physical Chemistry
      Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE