FIELD-ION MICROSCOPE STUDY OF MICROSTRUCTURAL FEATURES OF SOLAR COLLECTOR COATINGS

The nucleation and growth characteristics of the systems electroplated nickel on stainless steel and black chrome on nickel were investigated for thin coverages and for thick coverages utilizing the techniques of field ion microscopy (FIM) and s scanning electron microscopy (SEM). The SEM study shows that increasing the plating voltage and/or decreasing the nickel concentration in the plating bath produces finer overgrowths in the nickel/stainless steel system, whereas this trend is reversed for black chrome electroplatings on nickel field emission end forms. FIM analysis of the plated growths shows an epitaxial attachment at thin coverages (less than 50 atomic layers), whilst at thicker deposits (greater than 50 atomic layers) the overgrowth goes through a zone of excessive defect structure to a polycrystalline layer of the plated material with its own lattice structure. These results are consistent with earlier studies of Cu/W systems utilizing the deposition of copper through cementation, electroplating and flash evaporation. © 1979.