Abstract
The corrosion behavior of single titanium nitride (TiN) coating, and TiN coating with nickel phosphorous (NiP) interlayer deposited on Al 6061-T6 substrate was investigated in 0.6 M NaCl electrolyte at pH = 7 using long-term Electrochemical Impedance Spectroscopy, potentiodynamic polarization, and microscopic observations. Also, the surface morphology and chemical composition of the coating surface were characterized using Scanning Electron Microscopy. The duplex-coated aluminum alloy showed more corrosion resistance than the single TiN coated specimen through the blocking of top layer pinholes at all times of exposure. Then the simultaneous effect of pH, temperature, and Clˉ concentration on corrosion current density of NiP/TiN coated aluminum alloy was studied by employing the Central Composite Experimental Design method. The pH had the maximum effect on corrosion current density among all the parameters, followed by temperature and Clˉ concentration. The corrosion behavior of NiP/TiN coating at different pH levels (2, 7, 12) demonstrated 25 times reduction of corrosion current density in an alkaline environment compared to an acidic solution.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
