Study of Adherent Oxide Scales

Abstract

Previously reported studies had shown that indigenous sulfur normally present in the approximately 1-40 ppm range significantly affected the scale adherence of both alumina and chromia formers. In isothermal studies involving the oxidation of the model chromia former, Ni-40 wt. % Cr, visual examination of alumina crucibles containing test specimens and subsequent analytical chemistry measurements showed that protective chromium oxides exhibited less volatility on high purity as compared to normal sulfur-containing alloys. While the absolute amount of chromium evaporated was small, higher purity (lower sulfur) alloys repeatedly showed less chromia volatilization. For cyclic tests involving sulfur-bearing (SO2-O2) environments, sulfur penetration of chromia scales occurred regardless of the purity of the alloy or whether or nor yttrium had been added to the normal purity alloy. Oxidation, Oxide scale adherent, Oxide scale formation, minor element effect, Sulfur, Protective coatings, Oxidation. (jes)

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Document Details

Document Type
Technical Report
Publication Date
Oct 27, 1989
Accession Number
ADA215189

Entities

People

  • J. G. Smeggil

Organizations

  • United Technologies Corporation

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Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Alloys
  • Analytical Chemistry
  • Base Lines
  • Chemical Analysis
  • Chemical Compounds
  • Chemistry
  • Classification
  • Crystal Structure
  • Engineering
  • Grain Boundaries
  • Materials
  • Materials Science
  • Metallurgy
  • Military Research
  • Security
  • Spectra
  • X Rays

Readers

  • Electrochemical Engineering/ Fuel Cell Technologies
  • Materials Science and Engineering.
  • Thin Film Deposition Science.