Tribo-corrosion shortens the service life of polymer brake coatings exposed to concurrent wear and saline attack. Here, a polyimide (PI) coating reinforced with polydopamine (PDA)-modified Al 2O 3 whiskers is reported. The PDA layer endows the whiskers with strong interfacial adhesion and uniform dispersion in the PI matrix. In dry-sliding tests, the neat PI exhibits a friction coefficient of 0.356, which increases to 0.50 for the composite, while the wear rate decreases by 46% (from 4.82 × 10⁻⁷ to 2.60 × 10⁻⁷ mm 3 N -1 m -1). Under a separate 5   wt% NaCl salt-spray test, it endures over 15 days without visible corrosion, whereas the pure PI coating exhibits severe degradation. The tensile strength is enhanced from 91   MPa (neat PI) to 96   MPa in the composite, and the storage modulus exceeds 3.5   GPa, indicating higher load-bearing capacity. These gains stem from the PDA-whisker interface, which transfers load, suppresses filler pull-out, and blocks crack/ion transport paths. This work demonstrates a viable route to high-performance tribo-corrosion-resistant brake coatings via PDA-functionalised ceramic whiskers.