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. •P content of Ni-P coating with 1 gr/lit Cu reduced by increasing the pH of the solution from 4.5 to 9.•P content of Ni-P coating decreased when the rotating speed of the bath was increased from 200 rpm to 600 rpm.•Increasing the rotating speed from 200 rpm to 400 rpm reduced the corrosion resistance. However, wear resistance increased.•Optimum corrosion resistance was obtained in coatings with pH = 4.5 & Ni-P-Cu coating at the rotating speed of 200 rpm.•Ni-P-Cu nano-composite coatings have higher wear resistance compared with the Ni-P coating.