Abstract
Many military applications require that conversion coatings for aluminum alloys provide high corrosion resistance while retaining low electrical contact resistance. In this paper, the performance requirements for Class 1A and Class 3 conversion coatings established in Military Specifications MIL-C-81706 and MIL-C-5541E are summarized. The corrosion resistance and electrical contact resistance of actual Class 1A and Class 3 coatings are presented. Results show that the required levels of performance are usually achieved on wrought alloys, but not on cast alloys. The corrosion resistance and electrical contact resistance of Cr-free conversion coatings has also been examined. Results indicate that the required performance levels are rarely achieved on any type of alloy substrate. Last, corrosion and electrical properties of coatings formed using methods based on low-toxicity alkaline oxide coatings procedures are described. Results from initial attempts to produce highly corrosion resistant coatings with low electrical resistance are presented.
Original language | English |
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Journal | NACE - International Corrosion Conference Series |
Volume | 1998-March |
State | Published - 1998 |
Event | Corrosion 1998 - San Diego, United States Duration: Mar 22 1998 → Mar 27 1998 |
Bibliographical note
Publisher Copyright:© 1998 by NACE International.
Keywords
- Conversion coatings
- Cr-free conversion coatings
- Electrical contact resistance
- Electrochemical impedance spectroscopy
- Salt spray exposure
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- General Materials Science