Development of High Speed Lead Plating and its Applications

SummaryA high speed lead plating process has been developed. The bath contains, per gal US, Pb(BF4)2 62·5 oz, HBF4 and H2BO2 ach 6 oz and hydroquinone 1·3 oz. The optimum temperature is 160°F and cathode surface velocities of 0–150 ft/min have been evaluated. Limiting current densities up to 3100 A/ft2 and average operating current densities up to 1000 A/ft2 are possible. Deposits are fine grained and cover basis metal defects even with coatings 0·1 mil or less. Brushing the basis metal and especially interrupting the lead deposition to brush the deposit reduces porosity. Coatings 0·05 to 0·1 mil thick so produced on steel when tested resisted corrosion by shellac better than terne and tinplate and were satisfactory in water-base paints. However, lead coatings on steel have poor solderability. Salt spray tests confirm the superiority of the deposits produced from the hydroquinone bath with or without brushing treatments. Copper and tin strikes were of no value in corrosion or solderability tests. Power an...