Effect of electroplating time on microstructure, corrosion and wear behaviour of Ni-P-W-TiO2 coating

Abstract

Ni-P-W-TiO2 coating has been deposited on the AISI 304L steel substrate using the electroplating method. Electroplating has been performed at 30, 45, and 60 min, and the effect of electroplating time on microstructure, corrosion and wear behaviour has been investigated. The coatings have been characterized by use of scanning electron microscopy (SEM). In order to investigate corrosion resistance, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests have been used in 3.5% of NaCl aqueous solution. A pin on disk test has been used to test the wear resistance of uncoated and coated samples. Sample micro-hardness has also been measured by the Vickers hardness test. Examination of the microstructure has shown that the best time for deposition is 45 min. The results of potentiodynamic polarization and electrochemical impedance spectroscopy tests are also consistent with microscopic images, and the results have shown that the coating created within 45 min has the highest corrosion resistance (7058 Ω.cm2) compared to coated sample within 30 (4142 Ω.cm2) and 60 (3059 Ω.cm2) minutes. Also, the results of the wear test and micro-hardness have shown that composite coating formed within 45 minutes has the highest wear resistance and micro-hardness (677 Vickers) compared to coated sample within 30 (257 Vickers) and 60 (638 Vickers) minutes.