Production of NiCr thin films by electrochemical methodand investigation of the properties

In this study, the structural, optical and corrosion properties of Nickel-Chromium (NiCr) thin films produced at different potential values by using constant potential and pulse reverse plating (PRP) technique have been investigated. The electrochemical bath contains Nickel Chloride (NiCl2) and Chrome Chloride (CrCl3). The reduction potentials of NiCr alloy were determined by using the cyclic voltammetry (CV) technique. Based on the CV curve, three different deposition potentials were selected as -1,0, -1,2 and 1,5 V vs Standard Calomel Electrode (SCE). Thin films produced on Ti substrate under the specified conditions were examined by X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), UV-Visible Light Spectrophotometer and Tafel extrapolation method. The structural examination of the films was carried out by changing the diffraction angle (2θ) between 18 ° and 100 ° by a step of 0,2 ° using the XRD technique. The chemical composition and surface morphology were analyzed by EDX and SEM, respectively. Using the data obtained from XRD analysis, it was determined that the films crystallized in surface centered (fcc) structure. In EDX analysis, it was seen that the composition of the films contained more than 97% Ni (i.e less than 3% Cr). From the XRD patterns, the interplanar distance, lattice parameter and particle size parameters of the crystal structure were calculated. In SEM images, the surface of the samples produced by PRP technique was more homogeneous, fine grained and smooth than the constant potentials. FTIR spectra were taken between 450-4000 nm and bands in this region were determined. Each graphic obtained from the films was found to be almost identical. UV-Visible Light spectroscopies of thin films were taken in the wavelength range of 300-800 nm and in generally, the constant potential samples were found to be more absorbance than those produced by PRP. The corrosion behavior of the films was investigated by Tafel extrapolation and it was found that the corrosion resistance of the films with constant potential was better.