Optimization, Prediction, and Characterization of Electroless Ni-W-P-nanoTiO2 Composite Coatings on Pipeline Steel

The present research reports an experimental study of Ni-W-P-nanoTiO 2 composite coatings deposited on API X60 low-carbon steel by the electroless method. Electroless bath parameters are optimized to attain maximum deposition rate using the Taguchi design (L9 orthogonal array). Analysis of variance was performed to find out the significance of individual parameters. A confirmation test was performed at the initial and optimal parameter combination obtained from the Taguchi analysis. In addition, the applicability of artificial neural network (ANN) was also examined for the prediction of deposition rate. An ANN 4-7-1 network accurately predicted the deposition rate with a correlation coefficient ( R 2 ) valued at 0.9820. Atomic force microscopy and field emission scanning electron microscopy were used to characterize the surface morphology, and energy-dispersive spectroscopy, and X-ray diffraction were used for compositional and phase study of the coatings. The corrosion behavior of nanocomposite coatings was tested in 3.5 wt% NaCl solution by potentiodynamic polarization. The optimum combination was achieved with 24 g/L of reducing agent content, 10 g/L of TiO 2 nanoparticles content, bath pH of 9, and a temperature of 80 °C.