Surface treatment of Cf/Al composites with immersion in aqueous solution containing Ce ions for corrosion barrier

In this study, Ce‐rich coating is investigated as corrosion inhibitor of carbon fibers reinforcement aluminum matrix (Cf/Al) composites. The coatings are obtained by immersion in aqueous solution containing Ce(NO₃)₃ onto composite surface, whereas the Ce‐rich coating process produces a coating with highly heterogeneous nature of the surface, but micro‐cracked layer with “dry‐mud” morphology. The coatings were composed of Ce‐rich nano‐particles, Ce‐rich particles with a sphere‐like morphology, which are agglomerated particles with diameter 4 ～ 8 nm and piled up for this coating. TEM observation for Ce conversion coating of the corresponding ring‐like SAED patterns could not be matched to any of the previously reported structures of cerium compounds. Results of high‐resolution XPS spectra of Ce3d obtained for Ce conversion coating show that the Ce3d spectra has several components with binding energies characteristic of Ce³⁺ and Ce⁴⁺. The Ce‐rich coating process produces effective corrosion protecting of Cf/Al composites, which is verified by electrochemical measurement results. The R_t values of coated sample are higher than those of uncoated sample, this confirms the better corrosion resistance of coating obtained after immersion treatment for Cf/Al composites.