Evaluation of a New Protective Coating for Porcelain Insulators
This paper describes the evaluation of a new elastomeric coating made from a silicone rubber compound for use on porcelain insulators. Field experience has shown that coated insulators have a lower flashover probability under wet contaminated operation than uncoated insulators.
Artificial testing and evaluation of RTV coatings in a salt-fog chamber
The electrical performance of room-temperature vulcanizing (RTV) silicone rubber insulator coatings under accelerated aging in a salt-fog chamber is reported. The RTV coatings were evaluated in fog produced from saline water at 900 mu S/cm conductivity. The effect of the contaminants deposited during dry band arcing was evaluated with respect to the performance of RTV coatings. The increase of the leakage current and the corresponding decrease of the contact angle on the surface of the coating are shown to be related to contaminants on the RTV-coated surfaces. Five cleaning methods to remove the contaminants from the coated surface are examined, using leakage current and contact angle measurement as indicators of their comparative effectiveness. >
Long Ceramic Beam Tubes for Accelerator Magnets
The ceramic beam tubes for the fast and abort kickers and the bucker and pinger magnets used at Fermilab must meet a number of exacting requirements. The tubes must be long and sufficiently straight so as not to limit magnet design. They must have wall strength capable of withstanding the atmospheric and mechanical forces encountered during construction and operation. Vacuum tight ceramic to stainless steel transitions must be of reasonable cost; they must also withstand high temperature processing and remain vacuum tight to the 10/sup -9/ Torr range. To remove the possibility of static charge buildup each tube must have a surface coating of indium oxide applied to the inner wall. This thin coating is difficult to achieve and requires the most careful attention to detail. The methods used at Fermilab to achieve these goals are presented in this paper.