Polyol Electroless and Electrodeposition of Nanostructured Ni-Co Films and Powders

Abstract

It has been demonstrated that the application of an electric field enabled the so-called polyol method at temperatures lower than the refluxing temperature of 194°C, thereby producing Ni-Co nanostructured magnetic films without wasteful powder precipitation. At the refluxing temperatures there was an inverse relationship between the magnitude of the applied electric field and the thickness of the deposited film. This surprising result has been postulated to be due to a localized increase in the pH close to the electrode surface inhibiting metal deposition. At the lower temperature of 160°C films could only be deposited in the presence of an electric field with only a small amount of powder being synthesized. Again the compositions of these magnetic films suggest that their deposition involved the electroless mechanism. At the much lower temperature of 100°C, film formation appeared to be due to simple electroplating, without any involvement of the electroless process.