Abstract
In electroplating on the surface of buffed cold rolled steel sheet in stannous sulfate bath, the effects of alkali cleaning or acid pickling of the steel sheet on electroplated tin nuclei were investigated.
When the steel sheet was cathodically cleaned in 70g/l of sodium hydroxide solution at 1amp./dm2 for 20sec. or at 5amp./dm2 for 1sec., the number of nuclei deposited was about 4 times as many as that of no cleaning. On the other hand, when anodically cleaned, the number gradually decreased with the increase of treating time.
When the steel sheet was subjected to acid pickling in 7% sulfuric acid solution, there were observed undeposited parts after the operation of electroplating. When the sheet was anodically pickled for 20sec., its surface was etched and number of nuclei greatly decreased.
