PEDOT-functionalized carbon nanotubes for anticorrosive reinforcement of epoxy coatings on sintered NdFeB magnets

Solving the problems of interfacial compatibility and dispersibility between filler and epoxy resin (EP) can greatly improve the anticorrosion performances of epoxy coatings and expand their application field. In this work, carbon nanotubes (CNTs) were modified by poly(sodium 4-styrene sulfonate) and poly(3,4-ethylenedioxythiophene) to form PCNTs hybrids, and the cathodic electrophoretic deposition method was used to form composite epoxy coatings on the surface of sintered NdFeB magnets for enhancing the anticorrosion performance. The corrosion resistance of PCNTs was evaluated by electrochemical and static immersion corrosion tests. Results indicate that PCNTs hybrids possess better distribution and compatibility in epoxy resin than CNTs hybrids, resulting in the anticorrosion performances of higher density of composite epoxy coatings on NdFeB magnets. Optimized EP/PCNTs possess a much higher | Z | 0.01 Hz of 4.41 × 107 Ω·cm2 and a much lower Jcorr of 9.648 × 10− 10 A·cm− 2 than that of EP (1.34 × 104 Ω·cm2 and Jcorr 4.436 × 10− 6 A·cm− 2), demonstrating superior corrosion resistance.