Control of electrodeposit properties of nickel and nickel alloy by pulse plating.

Pulsed-current electrolysis with various ratios of on-time to off-time have been applied to the deposition of Ni and Ni/Fe alloys from Watts and Ni/Fe baths.The electro-depositions of nickel and nickel-iron alloy on copper and mild-steel substrates using Watts and Ni/Fe baths have been investigated. The mechanical properties of micro-hardness and internal stress obtained using the EFCO stress-meter and X-ray diffraction were measured as a function of bath composition, on/off cycles,current density, types of plating and solution pH. The structure and composition of alloys deposited have been investigated using S.E.M and wet analyses. It has been shown that the composition of the Ni/Fe alloy deposits changed markedly with increasing current density and proved to be dependent on current density. Also, the composition and properties of electrodeposited Ni/Fe alloy have been related to the composition of electrolyte and the deposition conditions. Distinct differences between direct and pulsed processes revealed themselves in the surface characteristics, micro-hardness data, cathode current efficiency data, internal stress measurements, pH data, various current density and finally composition of platings. Implications of using pulse plating to control the quality of electrodeposits have been considered.