Corrosion Chemistry in Inhibited HDA.
Abstract
The constitution of Uninhibited HDA has been examined by Raman spectroscopy. The behavior of known and potential inhibitors of aluminum and stainless steel corrosion in HDA has been studied by n.m.r. spectroscopy, electrochemical techniques, X-ray photoelectron spectroscopy and scanning electron microscopy. The mechanism of inhibition has been established for both aluminum and stainless steel. For stainless steel, inhibition occurs because of plugging of anodic sites, which prevents growth and breakdown of the existing chromium (III) oxide film. Film breakdown on stainless steel in uninhibited HDA has been shown to be due to the transpassive effect. For aluminium, inhibition is also due to a film plugging mechanism which appears to inhibit pitting. Long term storage of Standard HDA in aluminium generates a very thick film on the metal surface which appears to contain alpha-AlF3 and alpha-AlF3.H20 as principal components. A number of new metal difluorophosphates has been synthesized, some of which are likely to resemble authentic Modified HDA corrosion products, and reactions of a range of metal fluorides with difluorophosphoric acid have been examined. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1980
- Accession Number
- ADA104772
Entities
People
- Michael F. A. Dove
- Norman Logan
Organizations
- University of Nottingham