| 摘要 |
1,070,456. Welding by pressure. SIEMENSSCHUCKERTWERKE A.G. May 6, 1965 [May 6, 1964], No. 19237/65. Heading B3R. [Also in Division H1] In the manufacture of selenium rectifier having an aluminium carrier electrode 2a and a tin-cadmium alloy counter electrode 2c a silver wire or tin-coated copper wire 3 with a flattened end is welded to the counter electrode by current passed between two closelyspaced electrodes in contact with the wire. A wire may be similarly attached to the carrier electrode or alternatively this electrode may be coated with a sprayed-on layer of a soft solder such as the tin-cadmium alloy of the counter electrode. The rectifier may be encapsulated in a lacquer containing a thixotropic agent. An epoxy resin lacquer is suitable and aluminium silicates such as bentonites and ammonium alkyl aluminium silicates may be included as thixotropic agents which both make dip coating of thick films possible and, due to their absorption properties, give the coating a low permeability to water vapour. When mixing the thixotropic agent and lacquer an intermediate solvent is not used as it would give rise to voids in the dried coating. If the area of contact between selenium and counter electrode is limited by an interposed insulating annulus the wires are bonded to the edge of each face instead of to the centre. |
