Accession Number:

AD0653723

Title:

CHEMICAL PHYSICS OF SURFACE REACTIONS OF METALS

Descriptive Note:

Final rept., 1 Jun 1965-31 May 1967

Corporate Author:

WESTINGHOUSE RESEARCH LABS PITTSBURGH PA

Personal Author(s):

• Gulbransen, Earl A.
• Tallman, Richard L.

Report Date:

1967-05-31

Pagination or Media Count:

127.0

Abstract:

A survey is made of studies at the Westinghouse Research Laboratories on the structure of oxide films and the formation of localized oxide growths on iron. Filamentary whisker growths are formed when iron is oxidized in dry oxygen at 400 to 500C. Long, blade-like platelets are formed at 450C in atmospheres containing both water vapor and a trace of oxygen. The oxide whiskers and the blade-like platelets produce fiber-texture patterns showing exclusively alpha-Fe2O3 diffraction. Selected-area electron diffraction patterns of individual growths indicate 1 that the most simple whiskers have a single axial screw dislocation and 2 that the blades are twinned on the blade-face plane. Growth mechanisms based on easy paths for diffusion along the axial dislocation in the oxide whisker and along the twin plane in the oxide blade- like platelet are proposed. Some calculations relevant to the internal diffusion mechanism in whiskers are presented.

Descriptors:

• *SINGLE CRYSTALS
• *IRON
• *IRON OXIDES
• *CRYSTAL GROWTH
• *WHISKERS(CRYSTALS)
• METALS
• NUCLEATION
• TRANSPORT PROPERTIES
• OXIDATION
• TWINNING(CRYSTALLOGRAPHY)
• ELECTRON DIFFRACTION
• THERMOCHEMISTRY
• DISLOCATIONS
• SURFACES
• ELECTRON MICROSCOPY
• CORROSION

Subject Categories:

• Physical Chemistry
• Properties of Metals and Alloys
• Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE