The Progress of Nickel Deposition in Recent Years

Exposure for 24 h to an atmosphere containing 10% sulphur dioxide, of controlled humidity, and at ambient temperatures, is shown to provide a method for porosity detection in a range of precious metal electrodeposits on several substrates commonly used under them. Both sulphur dioxide concentration and humidity control are attained simply and reproducibly for periods up to 24 h by generating the atmosphere within the test chamber by slow reaction of solutions of sodium thiosulphate, and sulphuric acid. For gold plated copper alloys the results obtained have been compared with those from the electrographic and 48 h sulphur dioxide—hydrogen sulphide tests. The comparison suggests the 24 h sulphur dioxide test may usefully complement and in certain cases replace either test, both for research and routine quality control.