Enhancing Surface Insulating Performance of an Epoxy Plate by Film Deposition with Meter-Scale Dielectric Barrier Discharge

Enhancing surface hydrophobic and insulating performances of epoxy (EP) materials is crucial for reliable operation of the outdoor high-voltage electrical equipment. In this paper, a meter-scale dielectric barrier discharge (DBD) reactor is designed with an optimized precursor feed path for homogeneous plasma generation to deposit a hydrophobic insulating film on EP plates. The space-resolved discharge characteristics of argon/hexamethyldisiloxane (Ar/HMDSO) are diagnosed to analyze the uniformity of the plasma. The variations of discharge characteristics and surface performances are evaluated under different substrate thicknesses (2-10 mm). The results indicate that a meter-scale uniform discharge is excited irrespective of the substrate thickness. The mean water contact angle is increased to 150.1° after the treatment for EP with a thickness of 2 mm, and the flashover voltage is enhanced by 15.1%, with the deviation in the meter scale no more than 4% and 2%, respectively. It is revealed by surface physical morphology, chemical composition, and charge dissipation measurement results that a continuous silicon film is deposited on EP inducing shallow traps that effectively suppress charge accumulation, thereby enhancing surface insulating performance. This study provides reference and guidance for the industrial application of DBD in the surface modification of large-scale insulating materials.