HARDENING AND SMOOTHING EFFECTS OF LIGNIN SULFONATES ON THE ELECTRODEPOSITION OF LEAD

The codeposition of lignin derivatives from an acidic lead electrolyte was investigated with respect to the nature of the derivative, the ad ditive concentration in the electrolyte and the current density. The l ignosulfonates of sodium and calcium were incorporated in the deposits up to a volume fraction of 1.1-1.2% whereas the codeposition of alkal i lignin was much lower. The lignosulfonates were dispersed in the dep osit as small inclusions which were distributed very evenly. A signifi cant hardening of the deposited lead, based on both grain refinement a nd dispersion strengthening by the included organic particles, occurre d.