High-Performance Anti-Corona Coating Based on WPU/EP/α-SiC/β-SiC/n-ZnO Composite System: Fabrication and Performance Evaluation Under Simulated Stator Bar Aging

With the demand for high-voltage electrical insulation systems increasing, the development of environmentally friendly anti-corona materials with reliable nonlinear electrical properties has become essential. In this work, a waterborne polyurethane/epoxy (WPU/EP) composite coating was fabricated using micron-sized SiC (α-SiC), nano-sized SiC (β-SiC), and n-ZnO as multi-scale fillers. Its microstructure, nonlinear conductivity, flashover characteristics, and electro-thermal aging performance were systematically investigated. The results indicate that the incorporation of α-SiC significantly enhances conductivity under high electric fields by forming conductive pathways, while β-SiC further improves nonlinear behavior through interfacial bridging effects. The addition of n-ZnO modifies interfacial characteristics and contributes to improved electrical response. Moreover, the flashover performance is strongly dependent on filler composition, showing a critical role of nano-fillers in charge trapping and transport regulation. Electro-thermal aging tests on simulated stator bars reveal that the developed coating exhibits improved resistance to degradation compared with conventional materials. These findings demonstrate the effectiveness of multi-scale filler design in tailoring the electrical and insulation performance of waterborne anti-corona coatings.