Tribological Properties of TiO2 Reinforced Nickel Based MMCs Produced by Pulse Electrodeposition Technique

Nickel-TiO2 composite coatings were prepared under pulse current conditions by co-deposition of TiO2 particles and nickel from a Watts type bath. The effect of TiO2 particle concentration was studied on microhardness, friction coefficient and wear resistance. The morphological features and the structures were studied by scanning electron microscope, X-ray diffraction analysis and 3D profilometry facilities. A wide particle size range (between 95 and 140 nm) was chosen to provide a high dispersion and load bearing ability for the co-deposited layers. It was determined that increasing the particle concentration in the electrolyte dramatically increased the co-deposited TiO2 particles in the coating. The results showed that the high concentration of TiO2 particles in the electrolyte yielded the highest amount of particles co-deposited in the plating layer. The influence of the co-deposited TiO2 volume on microstructure and tribological properties in the coating were investigated. The wear tests were carried out using a constant load by a reciprocating ball-on disk configuration. Wear loss and friction coefficients of Ni/TiO2 composites were decreased by increasing TiO2 content in the electrolyte because of the increasing content of TiO2 in the deposited layer. The change in wear mechanisms by changing TiO2 content was also determined.