The epitaxial crystal growth and surface form of fcc nickel electrodeposits from the nickel sulphamate bath, on smooth copper {100} faces, are studied systematically by electron diffraction. Current densities up to 600 mA cm−2 and thicknesses up to 60 000 Å are investigated. The results with the bath at 20 and 50°C, and unstirred, show quantitatively the effects of the bath temperature, and additional results show the effects of vigorous stirring at 50°C.At 50°C two main isostructural regions of current density and thickness are distinguished, subdivided into five subregions where the surface or subsurface form is different. In the single-crystal region, negligible twinning due to lattice misfit occurs, in marked contrast to the strong twinning in Ni on Cu {110} and {111} using the same bath and conditions. The development of oblique faces is studied and a new region is found at high current density where their development is again very slow or absent. Above a certain current density, varying with deposit thickness, co-deposition of Ni(OH)2 occurs, leading to twinning and random Ni crystals.
Grazing-incidence electron diffraction shows the structure and growth of face-centred cubic (fcc) Ni electrodeposits from a sulphamate bath on polished polycrystalline Cu, at 50 and 20°C, both with and without stirring, at current density (cd) i up to 600 mA cm−2 at 50°C, and thickness H up to 60 000 Å or more.Seven isostructural regions of i and H are distinguished, with boundaries approximately of the form H(i-i0)=constant. The effects of bath temperature and of stirring are shown in detail. Ni(OH)2 is co-deposited at cd where the current efficiency falls appreciably below 100%.In the main lateral-growth region the Ni crystals soon develop cube faces (thus layerwise growth) and hence preferred {100} orientation develops (in part also {111} at low i and H). At high cd, {110} and/or {210} outward-growth orientation is developed. The dependence of the spread of orientation about the mean, on i, H, stirring, bath temperature and type of orientation, is shown. It is compatible with these crystal growth and orientation processes and with the cations being incident practically normal to the surface elements of the `rough' deposit.
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