THE MECHANISM OF OXIDE FORMATION IN THE INITIAL STAGES OF OXIDATION
Abstract
The major experimental efforts during the report period were directed toward the achievement of a more precise definition of the oxide microcrystallites formed on the tungsten and tantalum substrates in the initial stages of the oxidation reaction. The field emission experiments revealed the existence of nuclei of a second phase on the surface by virtue of highly localized and sharply defined discontinuities in electron emission intensity. While the nuclei appear more or less simultaneously at regularly spaced intervals on the surface and their number remains approximately constant for specific crystallographic regions of the tungsten substrate, simultaneous nucleation is not observed in the region of tungsten or on any preferred crystallographic region of the tantalum sub strate. The non-simultaneous nucleation is apparently characterized by random location of nuclei (i.e., nucleating centers do not occur at regular intervals over the surface) and in many cases by an increasing field enhancement effect with increasing growth. This effect may be attributed to a relatively greater growth rate perpendicular to the substrate than parallel to it (i.e., whisker-like growth).
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 29, 1963
- Accession Number
- AD0403927
Entities
People
- D. W. Rausch
- K. L. Moazed
- M. G. Fontana
Organizations
- Ohio State University