Study of wear behavior of Ni-P-TiO2 composite coatings by optimizing coating parameters

Abstract

In present research work, optimization of wear performance of electroless Ni-P-TiO2 composite coatings is carried out using Taguchi orthogonal array design. Coating parameters (Nickel sulphate, sodium hypophosphite, titania particles and heat treatment temperature) are optimized with the help of L27 orthogonal array in order to improve wear performance of the composite coating. Heat treatment temperature and concentration of titania particles are found to be significant factors. Interaction between sodium hypophosphite and concentration of titania particles have significant effect on wear characteristics of the coating. The characterization of the coating is carried out through scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction analysis. The composite coatings have nodular structure with uniform distribution of titanium particles in as-deposited condition. After heat treatment at 400°C for one hour the coating transform into crystalline structure. The wear mechanism is also studied and found to be a mixture of abrasive and adhesive wear phenomena.