Environmentally-Induced Passivity of Aluminum Alloys and Aluminum Metal Matrix Composites
Final rept. 1 Oct 1987-30 Sep 1990
UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING
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This final report presents a summary of the work performed under Contract No. N00014-88-K-0034. One of the goals of the research carried out was to develop corrosion protection methods for Al-based materials which can replace the presently used chromate conversion coatings with modified surface layers of equal or even better resistance to localized corrosion. The past work first evaluated the use of rare earth metal chlorides REMC for the passivation of Al alloys and AlSiC by a simple immersion treatment. Very corrosion resistant surfaces have been obtained in this manner which did not show any localized corrosion during exposure to aerated NaCl for periods up to 60 days. In an attempt to shorten the passivation time, a passivation treatment in solutions of CeCl3, and CeNO33 has been developed. Very corrosion resistant surfaces have been produced in a process in which immersion in CeCl3 and CeNO33 was followed by an electrochemical treatment in Na2MoO4.
- Metallurgy and Metallography