摘要 |
An electrical insulator offering reduced sensitivity to pollution comprises a body of a glass or porcelain dielectric material with a semiconductor outside coating. This coating mainly consists of zinc oxide with at least one further metal oxide added to it to make its voltage-current characteristic non-linear, such that I=kV alpha where I is current, V is voltage, k and alpha are coefficients, and the value of alpha is between 20 and 50. The coating is between 0.05 and 0.5 mm thick. The further metal oxide is advantageously selected from bismuth, manganese, cobalt, chromium and antimony oxides.
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