Electrolytic oxygen evolution on Ni-P-Sc2O3 composite layers

Composite Ni-P-Sc2O3 electrolytic layers were obtained in galvanostatic conditions on a copper substrate at temperature 298 K at the current density 20 mA cm(-2), from a nickel electrolyte containing a suspension of 25-125 g crystalline Sc2O3 For comparison, Ni-P layers were also obtained in the same current conditions. The phase composition of the layers were investigated by the X-ray diffraction method using a Philips diffractometer and Cu K alpha radiation. The chemical composition of the layers was determined by the atomic absorption method using a Perkin-Elmer spectrophotometer. The cyclic chronovoltamperometric method was used to determine the behavior of the Ni-P-Sc2O3 and Ni-P layers as a function of their chemical and phase composition and also of KOH concentration in the solution. Using the potentiodynamic method, the polarization curve was plotted for the process of oxygen electroevolution from the 5 M KOH solutions. On this basis it was possible to determine the values of the Tafel equation parameters for the oxygen evolution process. These values were then taken as the criteria for oxygen evolution on the composite Ni-P-Sc2O3 layers and on the Ni-P layers.