Corrosion Behavior of a Carbon Network/Aluminum Matrix Porous Composite in Salinated and Acidic Environments

Through this work, a carbon network/aluminum matrix porous composite material was analyzed for its susceptibility to material degradation in sulfuric acid and seawater corrosive media. Simple potentiodynamic electrochemical testing was implemented, and from polarization curves, the Tafel coefficients and exchange current densities were obtained for a comparative analysis. The pseudo exchange current densities for corrosion of the composite material were compared to those found for Al 1235 and 6061-T6. By relating the pseudo icorr of these materials in each environment, an understanding regarding the relative propensity to corrosion was determined. According to the recovered data, the composite had the lowest pseudo icorr in all corrosion systems and was consequently inferred the least likely to corrode. The factor that primarily contests this conclusion is the material’s relatively large exposed surface area. The existence of carbon along the grain boundaries in the C/Al composite improved its corrosion behavior. Further discussion concerning the implication of β c is offered. Electrochemical impedance spectroscopic (EIS) tests were performed in the frequency range from 0.001 Hz to 100 kHz. An immersion corrosion test was conducted to calculate the corrosion rate in different environments. Morphological observation on the corrosion surface was also carried out to evaluate the corrosion product deposition on each material. View Full-Tex