THE CORROSION BEHAVIOR OF ALUMINUM-SILICON CARBIDE COMPOSITES IN AERATED 3.5-PERCENT SODIUM-CHLORIDE

The corrosion behaviour of aluminium 6061-T6 alloy and 6061-SiC compos ite in 3.5% NaCl was investigated. While alloy 6061 underwent pitting corrosion, the composite material exhibited two types of corrosion: (1 ) pitting and crevice attack around each SiC fibre, and (2) crevice co rrosion in surface voids or hair-line fractures. The pitting and crevi ce corrosion around the fibres were due to the accumulation of magnesi um at the fibre-matrix interface during composite manufacture. The eff ect of cerium inhibition was also examined with these materials, and w as shown to retard pit initiation for approximately 1-2 days.