ELECTROPLATING OF NI-CO ALLOY IN A SODIUM CITRATE BATH ON BRASS AND STUDYING SOME EFFECTS ON THE LAYER THICKNESS AND HARDNESS

Abstract

A nickel sulfate solution with a Co suspension was used to electroplate Ni-Co alloy coatings onto a brass substrate. The impacts of the plating bath's pH, temperature, length of time, nanoparticle concentration, and current density on the coating's composition were examined. The best conditions were (C.D. 2A/dm2 , 55oC, 60 min, and pH 8) deposit surfaces were examined by X-ray diffraction thin film and Vickers microhardness. The surface hardness peaked at 2 A/dm2 (278 HV), which is the greatest value possible. It is evident that more cobalt is deposited as the current intensity increases, raising the bath's cobalt concentration by more than 15 g/l. According to the results, the rate of Ni-Co deposition is affected by pH, rising from 7 to 9.5 while falling Co% at pH values over 7.5. At 33 °C, the layer deposition rate was 30 mg/dm2 .min, rising to 40 mg/dm2 .min at 63 °C, then dropping to 35 mg/dm2.min as the bath temperature increased to 73 °C. Low deposition rate and temperature were observed in cathodic deposits.