Amorphous metal foil for brazing copper electrical joints

Brazing of copper electrical conductors is of importance in power transformers, and uses a great amount of brazing material. The areas brazed are usually inside the coil, and consist of taps, leads, and splices. Since the brazing is done inside the coil care must be taken in the making of the joint to prevent insulation damage and annealing of the joint area due to the brazing temperatures. A new brazing foil with a lower melting temperature than the currently used AWS BCuP-5 [1] braze is on the market. This foil has an amorphous structure with a copper base, 7% phosphorous, and no silver. Due to its lower melting temperature there is less heat input in the base material during brazing, therefore, there is less likelihood of insulation damage, less annealing of the joint area, lower oxide buildup, and less time to effect a joint.