Circuit breaker having members coated with phosphate-chromate protective layers

摘要

A circuit breaker, operating in an insulating liquid dielectric environment, switchable between an open position and a closed position, is made of metallic sensing, tripping and supporting members, where a plurality of the members are coated with a dual protective film comprising a first layer containing zinc phosphate or iron phosphate about 0.00001 to about 0.0004 inch thick covered by an outside layer containing zinc chromate and/or zinc dichromate about 0.00001 to about 0.0004 inch thick, the protective film being resistant to the contacting liquid dielectric.