The influence of reactive-element coatings on the high-temperature oxidation of pure-Cr and high-Cr-content alloys

被引:82
作者
Hussey, RJ
Graham, MJ
机构
[1] Institute for Microstructural Sciences, National Research Council of Canada, Ottawa
来源
OXIDATION OF METALS | 1996年 / 45卷 / 3-4期
关键词
Cr2O3 films on Cr and high-Cr-content alloys; reactive elements; O-18/SIMS; transport processes;
D O I
10.1007/BF01046989
中图分类号
TF [冶金工业];
学科分类号
0806 ;
摘要
The influence of various reactive-element (RE) oxide coatings (Y2O3, CeO2, La2O3, CaO, HfO2; and Sc2O3) on the oxidation behavior of pure Cr, Fe-26Cr, Fe-16Cr and Ni-25Cr at 900 degrees C in O-2 at 5 x 10(-3) tory has been investigated using the O-18/SIMS technique. Polished samples were reactively sputter-coated with 4 nm of the RE oxide and oxidized sequentially first in O-16(2) and then in O-18(2). The effectiveness of each RE on the extent of oxidation-rate reduction varied with the element used Y2O3 and CeO2 coatings were found to be the most beneficial, whereas Sc2O3 proved to be ineffective, for example, for the oxidation of Cr. SIMS sputter profiles showed that the maximum in the RE profile moved away from the substrate-oxide interface during the early stages of oxidation. After a certain time the RE maximum remained fixed in position with respect to this interface, its final relative position being dependent on the particular RE. The position of the RE maximum within the oxide layer is also varied with the substrate composition. For all coatings O was found to have diffused through the oxide to the substrate-oxine interface during oxidation, the amount of oxide at this interface increasing with increasing time. The SIMS data confirm that for coated substrates there has been a change in oxide growth mechanism to predominantly anion diffusion. The RE most probably concentrates at the oxide grain boundaries, generally as the binary oxide (RE)CrO3. Cr3+ diffusion is impeded, while oxygen diffusion remains unaffected.
引用
收藏
页码:349 / 374
页数:26
相关论文
共 35 条
  • [1] TRANSPORT PROCESSES DURING THE GROWTH OF OXIDE-FILMS AT ELEVATED-TEMPERATURE
    ATKINSON, A
    [J]. REVIEWS OF MODERN PHYSICS, 1985, 57 (02) : 437 - 470
  • [2] BENNETT MJ, 1981, IAEA SPEC M HIGH TEM
  • [3] BENNETT MJ, 1988, R13107 AERE
  • [4] BENNETT MJ, 1983, HIGH TEMPERATURE COR, P145
  • [5] THE INFLUENCE OF IMPLANTED YTTRIUM ON THE MECHANISM OF GROWTH OF CR2O3 ON CR
    COTELL, CM
    YUREK, GJ
    HUSSEY, RJ
    MITCHELL, DF
    GRAHAM, MJ
    [J]. JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1987, 134 (07) : 1871 - 1872
  • [6] COTELL CM, 1990, OXID MET, V34, P173, DOI 10.1007/BF00665014
  • [7] THE INFLUENCE OF GRAIN-BOUNDARY SEGREGATION OF Y IN CR2O3 ON THE OXIDATION OF CR METAL .2. EFFECTS OF TEMPERATURE AND DOPANT CONCENTRATION
    COTELL, CM
    YUREK, GJ
    HUSSEY, RJ
    MITCHELL, DF
    GRAHAM, MJ
    [J]. OXIDATION OF METALS, 1990, 34 (3-4): : 201 - 216
  • [8] COTELL CM, 1987, P S HIGH TEMP MAT CH, V88, P268
  • [9] DOWNHAM DA, 1990, P INT S HIGH TEMP OX, P101
  • [10] THE INFLUENCE OF SUPERFICIALLY APPLIED OXIDE POWDERS ON THE HIGH-TEMPERATURE OXIDATION BEHAVIOR OF CR2O3-FORMING ALLOYS
    ECER, GM
    SINGH, RB
    MEIER, GH
    [J]. OXIDATION OF METALS, 1982, 18 (1-2): : 55 - 81