Assessment of Conductive Sites on Carbon-Fiber Reinforced Polymer

Carbon-fiber reinforced polymer (CFRPs) composites can drive galvanic corrosion of other metals with which they are in contact such as aluminum alloys (AAs) when exposed to aggressive environments. In these galvanic couples, CFRP behaves as a cathode, owing to the noble nature of carbon, whereas the coupled metal behaves as an anode that undergoes accelerated deterioration. To be able to control the corrosion, it is critical to understand the electrochemical activity of CFRP. In this work, a copper deposition technique was developed to quantify the extent of electrochemical activity and identify the exact location of electrochemically active sites on the CFRP. Optimization of the deposition parameters was performed by focused ion beam sectioning and viewing the Cu-deposited cross sections in a scanning electron microscope (SEM). Quantification of the electrochemically active area was done through large-area imaging by SEM and optical microscopy and image analysis. The top surfaces and cross sections of deposit/CFRP interfaces were investigated by viewing at high magnification to evaluate polymer coverage and surface defects.