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PHYSICAL AND CHEMICAL PROPERTIES OF PULSE-PLATED FeNi AND NiCo ALLOYS M. Lakatos-Varsányi, A. Mikó, B. Tury Bay Zoltán Institute for Material Science and Technology Fehérvári út 130, Budapest, Hungary |
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57Fe conversion electron Mössbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Ni-Fe coatings. The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt%Fe deposit reflected a microcrystalline NiFe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt%Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these FeNi pulse plated thin layers.
NiCo alloys have been deposited by pulse plating technique from Watts and chloride baths. Morphological analysis of the samples showed that the layer deposited from Watts bath performed granulated structure and the grain size was about 50nm. Contrary, the samples that were deposited from chloride bath represented rather columnar structure with some granulated grains. Analysis of the XRD spectra indicated that the deposited NiCo layer contains not only fcp, but mixed structure hcp-fcp structure. The samples were examined also by different electrochemical technique in order to compare the corrosion properties of the pulse plated layers. The difference in the morphological deviation can be a possible explanation for the difference in corrosion properties.