Ultrasound‐Assisted Nickel Electrodeposition on Carbon‐Fiber Fabrics for Improved Coating Uniformity and EMI Shielding of PA6 Composites

Nickel‐plated carbon fiber fabric reinforced polyamide 6 (Ni–CF/PA6) composites are promising candidates for lightweight electromagnetic interference (EMI) shielding components, but their shielding performance is strongly affected by the uniformity and continuity of the nickel layer within tightly packed fiber bundles. To address this issue, an ultrasound‐assisted electroplating process was developed for carbon fiber fabrics and compared with conventional electroplating. The ultrasound‐assisted process promoted nickel deposition inside fiber bundles and reduced the spatial variation of nickel distribution. Cross‐sectional observations showed that increasing the ultrasound power density promoted nickel deposition within the fiber bundles and reduced the black‐core region. Regional EDS analysis showed that ultrasound assistance increased the mean Ni content from 72.85 to 82.57 wt.% and reduced the coefficient of variation from 4.06% to 1.45%. The electrical conductivity of the nickel‐plated fabrics increased with electroplating time. The ultrasound‐assisted Ni–CF/PA6 composite showed an average EMI shielding effectiveness of 41.2 dB in the 8–18 GHz range. It also showed the highest flexural modulus among the three composite groups. Differences in nickel‐coating morphology were associated with changes in the local PA6 phase distribution and flexural response. These results demonstrate that ultrasound‐assisted electroplating promotes intrabundle nickel deposition and reduces regional variation in Ni content. This work provides a feasible route for improving the coating uniformity and multifunctional performance of nickel‐plated carbon fiber fabric reinforced thermoplastic composites.