Accession Number:

AD0631171

Title:

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

Descriptive Note:

Corporate Author:

INSTITUTE OF MODERN LANGUAGES INC WASHINGTON D C

Personal Author(s):

Report Date:

1966-04-01

Pagination or Media Count:

31.0

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. H2SO4oleum, 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

Subject Categories:

  • Coatings, Colorants and Finishes
  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE