Polynitroaniline as brightener for zinc-nickel alloy plating from non-cyanide sulphate bath

Abstract

Electro-polymerization of orthonitroaniline was carried out on graphite electrode in hydrochloric acid medium. Zinc-nickel alloy deposition was carried out in the presence of polynitroaniline in acid sulphate bath. The bath constituent and bath variables were optimized through Hull cell experiments. The current efficiency and throwing power were measured. High shift of potential towards more cathodic direction was observed in presence of addition agent. Corrosion resistance test revealed good protection of base metal by zinc-nickel coating obtained from the developed electrolyte. SEM photomicrograph shows fine-grained deposit in the presence of addition agent. The consumption of brightener in the lab-scale was 0-01 gL-1 for 1000 amp-h. © Indian Academy of Sciences.