OPTICAL STUDIES ON ANODIC OXIDE FILMS ON ALUMINIUM (I/II),

Abstract

OPTICAL ANALYSIS OF THE MECHANISM OF FORMATION OF ALPHA-ALUMINA FILM: Main constituents of the films produced in sodium and potassium bisulphate melts or their mixtures were confirmed to be alpha-Al2O3. The film formed in ammonium bisulphate melt contained an appreciable amount of gamma-alumina. The films formed in conc. H2SO4 or in conc. H2SO4+oleum, consist mainly of gamma-Al2O3, but by longer formation, it was partly converted to alpha-Al2O3. REFRACTIVE INDICES AND DOUBLE REFRACTION OF VARIOUS ANODIC OXIDE FILMS: Anodic oxide films such as oxalic, sulphuric acid films formed at normal anodizing conditions and at lower temperature (hard-coating), chromic, sulphamic, phosphoric, boric (plus sulphuric) acid films, Ematal and Kalcolor films and boric acid-formamide films developed by the authors, were observed under polarizing microscopy and the refractive indices were determined and the existence of doubly-refracting properties was checked. Refractive indices of these films are usually lower than pure crystalline or amorphous alumina (1.67 plus or minus). (Author)

Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1966
Accession Number
AD0631171

Entities

People

  • Tajima Sakae

Tags

DTIC Thesaurus Topics

  • Acids
  • Birefringence
  • Boric Acids
  • Films
  • Microscopy
  • Optical Analysis
  • Oxide Films
  • Oxides
  • Refraction
  • Refractive Index

Fields of Study

  • Materials science

Readers

  • Electrochemical Engineering/ Fuel Cell Technologies
  • Surface Engineering/Surface Coating Technology.
  • Thin Film Deposition Science.