EFFECT OF AC SUPERPOSITION ON ELECTRODEPOSITION OF LEAD DIOXIDE: THE DIFFERENCE OF SINGLE PH,ASE AND THREE PHASE RECTIFIERS

Electrodeposited lead dioxide finds extensive applications as an anode in the production of electrochemicals [I-41 esP e cially in the form of graphite substrate lead dioxide (GSLD) anodes [ 1,5-71 for applications in halates [1,2], perhalates [1,3] and ozone [8]. During such studies, it was observed that most of the GSLD anodes obtained from using single-phase rectifier gave better adherent and crack-free deposits as compared with the deposits got from the three-phase rectifier. Since single-phase rectifiers are known to have more of AC component (ripples) as against three-phase'rectifiers. this led to the study of the influence of AC superposition on DC during the electrodeposition of lead dioxide on graphite mbstrate. Not much information is available on the superposition of AC for electrodeposition of lead dioxide, although a few references [9-1 I] are available on the influence of AC superpositioh on the formation of lead dioxide on lead from sulphuric acid electrolyte. The present paper deals with the influence of AC superposition on DC during electrodeposition of lead dioxide on graphite substrate from lead nitrate-copper nitrate bath, keeping the anode under either stationary or rotating conditions. The stress measurement was also camed out.