Electrical properties of MgO-ZrO2 insulating coatings on different types of epoxies

Abstract

The insulating coating of MgO-ZrO2 was coated on Stainless-Steel-304 (SS) tapes by reel-to-reel sol-gel process for investigation of electrical properties under various pressures at room temperature (298 K) and liquid nitrogen temperature (77 K) for HTS/LTS high field insert coil. Solutions were prepared by using Mg and Zr based precursors, solvent and chelating agent, then the insulation was made on long-length SS substrate. Insulation thickness for 4, 8, and 12 dippings was determined to be 7, 12, and 15 μm, respectively. Three different types of stycast, 2850 FT/24 LV Black and Blue, and White Buecher Epoxy Resin were studied. Stycast thicknesses were varied from 32-18 μm, when the pressure was applied from 0 to 0.54 GPa. The thicknesses of insulating coatings and stycast were measured by using Environmental Scanning Electron Microscope (ESEM). Resistance, capacitance and High Voltage Breakdown (HVbd) of the samples were measured by using standard equipment. Then, dielectric constant and electric strength were calculated. An analytical model was modified by the experimental data. The results were presented graphically.