Surface treatments to reduce electrochemical corrosion on semiconducting glazed insulators

The many advantages achievable by the use of semiconducting-glazed (SG) insulators in high voltage transmission lines have been extensively examined in the literature /1,2/. Unfortunately, these insulators exhibit a short lifetime, especially when used in heavily polluted areas. Their degradation has to be ascribed mainly to the rectifying effect arising at the interface between the wet contaminant deposit and the semiconducting layer: even with optimal glaze formulation and manufacture, the unidirectional component of the surface current produces the electrochemical corrosion of the glaze, more evidenced where microstructural defects (bubbles, craters, etc.) are present /3/.