Examination of electrical insulating performance of Er₂O₃ ceramic coating under ion beam irradiation

Electrical insulating performance of Er₂O₃ coating samples with thicknesses of 1.0-2.4 μm have been examined under 1 MeV H⁺ and 2.8 MeV He⁺ ion beam irradiations at room temperature. The intrinsic conductivity of one sample has not changed significantly after the irradiation corresponding to the estimated damage of 2.2 × 10^-2 dpa (displacement per atom). A strong electric field of 1 kV/mm applied under the irradiation has not affected the conductivity of the sample. In the other sample, the intrinsic conductivities measured after irradiations have increased gradually with the ion fluence, while the estimated damage was as low as ∼1 × 10^-3 to 1 × 10^-2 dpa. Since significant change was not observed in the beam-induced conductivities measured under beam irradiations, local current paths might be generated in the coating layer or at small pits observed on the coating surfaces due to the irradiations.