METHOD FOR APPLICATION OF METAL COATING ON CURRENT-TRANSMITTING SURFACES OF CONTACT JOINTS Russian patent published in 2016 - IPC C23C26/02 

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, in particular to installation, repair and maintenance of electrical equipment. Method of applying a protective metal coating of a low-melting alloy based on bismuth on current-conducting surface of contact components of contact connections includes decontamination and degreasing current-conducting surfaces, application of flux, removing flux residues and sawdust, coating current-conducting surfaces of fusible alloy based on bismuth. Fusible bismuth-based alloy is used, having a melting temperature range of 44-95 °C and following composition, wt%: bismuth 44.0÷99.993, indium 0.001÷55.994, tin 0.001÷28.0, lead 0.001÷40.0, cadmium 0.001÷25.0, zinc 0.001÷25.0, copper 0.001÷10.0, aluminium 0.001÷12.0. Before application of fusible alloy based on bismuth, method includes heating to temperature 49-100 °C said fusible alloy based on bismuth and tool for its application and contact part. In special case of invention current-conducting surfaces of contact parts of movable opened contact connections are coated with metal coating from bismuth alloy, in which content of indium is not less than 49 wt%.

EFFECT: reduction of transient electrical resistance of contact connections, stabilisation of its value at level of initial assembly throughout service life thereof, reduced power consumption and time spent on application of metal coating and broader applications.

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