THE GALVANIC CORROSION OF SIC MONOFILAMENT/ZE41 MG METAL-MATRIX COMPOSITE IN 0.5 M NANO3

The effect of composite constituents and dissolved O2 on the corrosion behavior of a SiC monofilament/ZE41 Mg metal-matrix composite (MMC) exposed to 0.5 M NaNO3 was studied. The SiC monofilament (MF) (which consisted of a carbon core, a layer of chemical-vapor deposited SiC, and an outer carbon-rich surface) supported cathodic current densities comparable to that of graphite. The corrosion of pure Mg and a ZE41A Mg alloy was not affected by dissolved O2. Corrosion rates of the MMC, however, increased with dissolved O2 since the MFs were effective O2-reduction sites, which enchanced galvanic corrosion.