Effect of SiC doping on corrosion behavior of Cf/Mg composites

Abstract

Although SiC doping has the potential in improving the mechanical properties of magnesium matrix composites, the effect of SiC doping on the corrosion resistance of Cf/Mg composites should be investigated to assess its service life in application. In this paper, SiC is doped into carbon fiber preforms by precursor infiltration and pyrolysis (PIP), and the morphology, phase, and composition of surface and cross-section of SiC doped Cf/Mg composites before and after corrosion test in NaCl solution are characterized. The electrochemical test results reveal that the corrosion potential (Ecorr) of SiC doped Cf/Mg composites is similar to that of Cf/Mg composites, the corrosion current density (icorr) of SiC doped composites increases by one order, and the corrosion resistance (Rp) of SiC doped composites is 274.5 Ω lower than that of Cf/Mg composites. The increase in the number of interfaces in composites due to the doping of SiC makes the corrosion solution easier to enter into composites. Then the contact probability between solution and the matrix raises, thus the carbon fibers and magnesium alloy are likely to form more corrosion galvanic couples in the solution, which results in the higher corrosion rate of SiC doped Cf/Mg composites than that of undoped composites.