Galvanic Corrosion of Aluminum-Matrix Composites
Technical rept. no. 2, 1 Mar-31 Dec 1990
MASSACHUSETTS INST OF TECH CAMBRIDGE H H UHLIG CORROSION LAB
Pagination or Media Count:
Galvanic-corrosion rates of Al-matrix composites were high in aerated chloride-containing solutions. Oxygen reduction was found to be the primary cathodic reaction. Aluminum corroded by pitting. The type of noble constituent i.e., graphite, SiC, or TiB2 also affected galvanic-corrosion rates. For example, results indicated that the galvanic-corrosion rate of Al should be about 30 times greater when coupled to graphite than when coupled to SiC or TiB2. In dearated solutions, galvanic corrosion was negligible even if chlorides were present. The galvanic-corrosion rates were determined using the zero- resistance ammeter technique and from potentiodynamic polarization diagrams of ultrapure Al, 6061-T6 Al, graphite fiber, SiC, TiB2, and a commercial graphite fiber6061-T6 Al metal-matrix composite.
- Laminates and Composite Materials