GALVANIC CORROSION BETWEEN SIC MONOFILAMENT AND MAGNESIUM IN NACL, NA2SO4 AND NANO3 SOLUTIONS FOR APPLICATION TO METAL-MATRIX COMPOSITES

Galvanic corrosion of SiC monofilament (MF) coupled to pure Mg and ZE41A Mg alloy was studied using the potentiodynamic polarization technique in concert with the mixed-potential theory. Corrosion penetration rates of Mg were generally equal to 1 cm year-1 in de-aerated and oxygenated 3.15% NaCl, 0.5 M Na2SO4 and 0.5 M NaNO3 solutions. Galvanic corrosion penetration rates varied from 0.046 to 7.3 cm year-1, depending on solution oxygenation and the exposed region of SiC MFs. NaF was very effective in reducing galvanic corrosion rates in de-aerated 0.5 M Na2SO4 and 0.5 M NaNO3, modestly effective in oxygenated 0.5 M Na2SO4 and 0.5 M NaNO3 and ineffective in 3.15% NaCl.