| 摘要 |
PROBLEM TO BE SOLVED: To obtain good plating free from blobs and unequalness by providing the entire part of the bottom of a plating cell with a fine air bubble generating source and an atm. foam generating source in the upper part of this source. SOLUTION: The bottom of the plating cell 1 is provided with the air bubble generating source 2 consisting of a perforated board made of a fluororesin for generating fine air bubbles of a diameter of 5 to 100μm over the entire part thereof and is provided with the air bubble generating source 3 having holes 3A for generating the large bubbles of a diameter of 1 to 3cm apart a distance of about 10cm in the lower part of a piping above this source. As a result, a plating liquid 5 is forcibly stirred and the air bubbles are dispersed and are made uniform so that the concn. of dissolved oxygen is maintained at 2 to 4ppm. In such a case, the ventilation quantity of the fine air bubbles is specified to 1 to 21/min of plating liquid 11 and the ratio of the fine air bubbles to the atm. foam is preferably specified to 2:1. The application of the plating which is free from the blobs and unequalness and has the improved quality is thus made possible.
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