Characterization of thin solid films containing yttrium formed by electrogeneration of base for high temperature corrosion applications

Mixed water–ethyl alcohol solutions of Y(NO3)3, 6H2O at 0.01 M were used for cathodic electrodeposition of Y(OH)3 thin films on Ni–20 wt.% Cr–1.5 wt.% Si substrate. Y(OH)3, xH2O deposits were obtained using a conventional three electrode cell. Current density and duration of deposition were optimized in order to obtain thin (<1 μm), uniform and adherent films. These deposited films were further transformed by thermal treatment into Y2O3 coatings, expected to increase the high temperature oxidation resistance of the substrate. Thermal stability, microstructure and formed phase of as deposited films and thermally treated films were characterized by differential scanning calorimetry (DSC), optical microscopy (OM), scanning electron and atomic force microscopies (SEM, AFM), inductively coupled plasma-optical emission spectroscopy (ICP-OES) and X-ray diffraction.