Effect of Axial Potential Distribution of Carbon Fiber on the Interfacial Performance of Carbon Fiber/Epoxy Composites in Anodizing

Anodic oxidation of carbon fibers has attracted considerable attention for interfacial modification of composites due to its advantages of continuous processing capability and uniform surface modification. However, the mechanism by which the axial potential distribution along carbon fibers affects surface modification behavior and interfacial performance remains unclear. In this study, the axial potential distribution of carbon fibers during anodic oxidation was investigated by regulating the electrode potential, and its effect on the interfacial properties of carbon fiber/epoxy composites was analyzed. The results show that: 1) the axial potential of carbon fibers decreases progressively with increasing distance from the anode plate. This decay is caused by the combined effects of the intrinsic resistance of the fibers and the conductive loss of the electrolyte, which consequently limits the effective region of the electrochemical reaction; 2) within the effective reaction region, a moderate increase in the fiber potential can significantly improve the interfacial performance of the composites, whereas an excessively high potential leads to degradation of interfacial properties; 3) a smoother and more uniform potential distribution is more favorable for achieving strong interfacial bonding.