Abstract
Usually the covering power value of the chromium plating bath deviates markedly when measured by Hull cell test. Experiments were carried out in order to investigate the cause of the deviation, and to find the better pre-treating method of the cathode which gives better reproducibility in the test result. Results are as follows:
(1) Cyanide bath dipping and chemical polishing of the cathode (copper), especially the latter, increase covering power value remarkably.
(2) In chemical polishing the brighter the surface of cathode, the less was the deviation.
(3) The least deviation was obtained by using the cathode uniformly electro-plated about 10 microns thick.
