The influence of pH, rotating speed and Cu content reinforcement nano-particles on wear/corrosion response of Ni-P-Cu nano-composite coatings

Nano-composite coatings with nano particles contents from 1 to 7 gr/lit, with the electroless bath pHs of 4.5, 7, 9; and electroless bath rotating speeds of 200, 400 and 600 rpm were produced. Microstructural/elemental analyses were performed by various techniques. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were used to study corrosion behavior. Wear resistance of the coatings was assessed by ball on disk wear test. Results showed that wear resistance of the coatings was improved at higher concentration of particles and by increasing the pH of the electroless bath as well. These conditions reduced corrosion resistance of the coatings, increased phases such as Cu2P7, CuP2, and reduced the P content in the Cu nano-composite coatings.