G. Saravanan

Effect of pulse parameter on pulsed electrodeposition of copper on stainless steel

Abstract The pulsed electrodeposition of copper on stainless steel has been studied in copper sulphate bath and the effect of duty cycle and frequency on the thickness and current efficiencies were compared at 50°C and at room temperature with average current density of 4 A dm−2. A new strike bath based on cupric chloride and hydrochloric acid was developed for the first time. The Cu coatings were characterised by SEM, AFM and XRD. Crystallite sizes of Cu coatings were calculated for various duty cycles from the Scherer’s equation. The deposits were smaller nodules and fine grained.

Nanocrystalline zinc–nickel alloy deposition using pulse electrodeposition (ped) technique

Abstract Zinc–nickel alloy was electrodeposited on stainless steel using pulse current deposition (PED) from a chloride–sulphate bath. Duty cycles were varied between 10 and 80% and frequency was changed from 10 to 100 Hz. The deposit characteristics were analysed using SEM, XRD and AFM and the results are presented in this paper. The corrosion resistance of zinc–nickel alloy deposited from direct current deposition (DCD) has been compared with that of the deposit obtained by pulse current using the electrochemical impedance spectroscopy method.

Electrodeposition of zinc–nickel alloy by pulse plating using non-cyanide bath

Abstract In this study, zinc–nickel electrodeposition was carried out in a sulphamate bath at pH 3–4 by pulse plating and the deposits obtained were characterised by measuring microhardness, surface roughness and by employing SEM, XRD, AFM techniques. The corrosion behaviour of the deposits was evaluated by potentiodynamic polarisation. The deposits obtained by pulse plating have an increased Ni content, thought to be responsible for an improved corrosion resistance.

Influence of CH3SO3H and AlCl3 in direct and pulse current electrodeposition of trivalent chromium

Abstract Comparison of direct and pulse current electrodeposition of the trivalent chromium from urea formic acid as a complexing agent was studied in detail. The influences of CH3SO3H and AlCl3 on the properties of the deposit were also studied. The presence of CH3SO3H exhibits higher current efficiency and better corrosion resistance because of its higher hydrogen overpotential. The pulse current electrodeposition leads to growth of β-Cr. The corrosion studies were conducted by potentiodynamic polarisation and electrochemical impedance spectroscopy. The morphology of the deposits was characterised by scanning electron microscopy (SEM) and X-ray diffraction.

Effect of AlCl3, CH3SO3H on thickness, current efficiency and corrosion properties of brush plated Cr(III) formate urea baths

Abstract Brush plating technique was used to deposit trivalent Cr for the first time and effects of AlCl3 and methane sulphonic acid (CH3SO3H) in the trivalent Cr bath was studied. Advantages of brush plated Cr on suitable substrate produced by selective area deposition process with required thickness was investigated. Owing to its portability, flexibility and easy to operate, brush plating has found increasing use in industry. The main applications are for repair and resizing purposes. Brush plated Cr on brass substrate has been investigated using XRD, SEM and AFM. X-ray diffraction analysis revealed that the brush plated Cr(110) was crystalline. Uniform surface coverage of the substrate by granular morphology was observed from SEM and AFM. CH3SO3H increases the hydrogen overpotential on Cr deposition, therefore current efficiency and thickness increased. Cr coated from bath containing both AlCl3 and CH3SO3H have better corrosion resistance due to high charge transfer resistance R ct and very low I corr than Cr(III) bath without these additives.