Control of concentration of each constituent in plating bath is indispensable to guarantee the product quality of electrogalvanizing steel sheet. An on-line analysis system of electrogalvanizing baths was developed using a microdroplet analysis method. This system consists of a sampling unit, a multichannel fluorescent X-ray spectrometer, and a computer. The plating solution is sampled, diluted by pure water and dropped onto the formed filter paper. Then it is dried and analyzed in a vacuum with fluorescent X-ray spectrometer. The sequence of these operations and the data processing proceed automatically by control of the computer. The characteristics of this system are as follows.
(1) Analysis in a vacuum enables to analyze light elements.
(2) Sufficient correction for the interactions among elements improves the accuracies of both light and heavy elements.
(3) Various plating solutions and chemical treatment solutions are analyzed in parallel.
(4) The state analysis of Cr3+ and Cr6+ is made automatically.
(5) The coating weight and composition of the electroplated film are also analyzed at intervals of the analysis of plating solutions.
This system was installed at the electrogalvanizing line in Chiba Works in April 1985, and has been successfully operating.
