Nickel nanocrystalline coatings were electrodeposited by using direct and pulse current in a Watts-type bath. The current densities were 2, 10, 30, 50 and 100 mA cm -2 and the substrates were with {111} and {400} texture. Scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) were employed to study the effect of electrodeposition current density on morphology, texture and grain size of deposits. The results showed that the texture and morphology of deposits were changed at 30 and 50 mA cm -2 on the substrates with {111} and {400} texture components, respectively. The texture of deposits were changed from {220} to {200} and the morphology was changed from spherical to mixed morphology (pyramidal and blocky) by increasing the current the current density. This is attributed to the decrease in hydrogen adsorption at higher current density. In pulse electrodeposition the change of morphology and texture on substrate with {111} texture component was postponed to higher current density and happened at 100 mA cm -2 . The grain size of deposits on substrate with {111} texture component was higher than that on substrate with {400} texture component because of higher nucleation rate occurs on substrate with {111} texture component. Because the hydrogen adsorption and the Ni ions concentration are both increased on the substrate during the pulse current electrodeposition, the deposits with smaller grain size were obtained. Electrochemical impedance spectroscopy (EIS) showed that the hydrogen adsorption occurred on the substrate surface had a great role on the subsequent change of texture and morphology. Key Words Nickel, nanocrystalline, electrodeposition, corrosion, passive layer, mott-schottky.
