Effect of electroplating temperature on microstructure, corrosion, and wear behavior of Ni-P-W-TiO2 coating

Abstract

Nickel-phosphorus-titanium oxide coating was fabricated on the AISI 304L steel substrate using the electroplating method. Electroplating was performed at temperatures of 55, 60 and 65 °C, and the effect of electroplating temperature on microstructure, corrosion behavior, and wear behavior was investigated. The coatings were characterized by use of scanning electron microscopy (SEM). In order to investigate corrosion resistance, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were performed in 3.5% of NaCl aqueous solution. A pin on disk test was employed to investigate the wear resistance of uncoated and coated samples. Sample micro-hardness was also measured by the Vickers hardness test. The results of potentiodynamic polarization and electrochemical impedance spectroscopy tests results showed that the coating created at temperature of 60 °C had the highest corrosion resistance (7058 Ω.cm2) compared to coated sample at temperature of 55 °C (2115 Ω.cm2) and 65 °C (2289 Ω.cm2). Also, the results of the wear and micro-hardness test showed that composite coating formed at temperature of 60 °C had the highest wear resistance and micro-hardness (677 Vickers) compared to coated sample at temperature of 55 °C (411 Vickers) and 65 °C (536 Vickers).