HALOGEN PASSIVATION STUDIES
Abstract
This report includes data on the nature of passivation of metal surfaces with fluorine and fluorine compounds, the composition of passive films formed, and the deleterious effect of atmospheric moisture on passive surfaces Fluorination reactions reach completion on stainless steel, nickel and aluminum alloy surfaces very rapidly. The surface films formed range from 5 to 20 A in thickness and grow at the expense of the oxide films. The apparent film thickness on copper and Monel surfaces continues to increase slowly over an extended period of time. Exposure of passive films to a humid atmosphere produces hydrated metal fluorides which cause secondary fluorination reactions upon reexposure of the surfaces to fluorine. The passive films formed by exposure to chlorine trifluoride and chlorine pentafuoride were comparable in thickness to the films formed by fluorine gas, contained metal chloride species, and were less resistant to humid air attack. Fluorine gas appears to be the most effective agent for passivation of metals. Adequate passive films are formed at all pressures within 0.1 to 1.4 atmospheres for a period of 15 to 30 minutes. Stepwise increase in concentration is unnecessary for passivation of metals, and slight deformation of metal surfaces does not destroy the passive films.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1967
- Accession Number
- AD0805953
Entities
People
- N. A. Tiner
- S. K. Asunmaa
- S. M. Toy
- W. A. Cannon
- W. D. English
Organizations
- Douglas