Structure and Space Charge Inhibition Performance of Reactive RF Magnetron Sputter Deposited Al2O3 Thin Film on the Fiber Surface

Abstract

Abstract-Cellulose insulation paper/pressboard has been widely used in HVDC transformers. In this study, the aluminum oxide function film was deposited on the cellulose insulation pressboard surface using reactive radio frequency (RF) magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy (SEM) and the X-ray photoelectron spectroscopy (XPS). The influence of the deposited function film on the space charge injection/accumulation behavior was investigated. SEM and XPS results show that the nano-structured Al 2 O 3 film was successfully fabricated on the fiber surface. The oil impregnated sputtered pressboard presents apparent space charge suppression effect. The obtained band gap energy (Eg) of Al 2 O 3 is 7.39 eV. The nano-structured Al 2 O 3 film introduces a new trap band which is helpful for the charge inhibition.