The process of internal oxidation of silver cadmium alloys is used for the prodn. of silver cadmium oxide materials with 5-15 wt.% cadmium oxide for switch gear with a high switch number. It prevents contact erosion in low tension switch gear such as air break contactors, protective circuit breakers and motor protection. The mild oxidation of the AgCD sheet was prevented as follows:- A cold plate of a AgCd alloy is pressed together with a silver or silver-alloy plate heated to 300-950 degrees C. in a hydraulic press with a pressure of 0.5-5 t./cm.2, the bonded sheet is then rolled in one pass with a 30-70% reduction and internally oxidised at 600 degrees c., 700 degrees C., pref. 800 derees C., under oxygen pressure of 1-5 at. pref. 2 for 24 hours. After the internal oxidation blisters cannot be detected on the silver layer.
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