German silver was tinned at three temperatures with solder containing 17 different impurities at up to five different concentration levels. The tinning process was carried out in a wetting balance. After this, the samples were subjected to corrosion and tested in a wetting balance again. It was established that bismuth at high concentration levels has a corrosion resistant effect which gives superior solderability. Silver, aluminium, bismuth, cadmium and copper, in amounts accepted by specifications, make the tinned surface unsolderable after corrosion. Statistical evaluation of a large number of tests — 1755 tests with 21,060 evaluated points — gave valuable information on how a wetting balance curve should be evaluated and which criteria should be established for good soldering.
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