Pulse Eletrodeposition of Ni/nano-Al2O3 Composite Coatings on Cast Iron Cylinder Liner

The hardness has been increased from 308 HV to 1050 HV through conventional Watts bath and by applying Taguchi's optimization technique with optimum parameters of pulse frequency 120 Hz, duty cycle 40% and peak current density 0.7A/cm2. The lubricant's pH (4) and stirring speed (400 rpm) are the foremost parameters for increasing the hardness of the coating.

Furthermore, the pulse current (PC) produces homogeneous distribution of Al2O3 particles in the Ni matrices. The chemical composition, surface morphology, crystal structure, adhesion, coating thickness and the corrosion resistance of the optimized liner specimen of deposited Ni/nano-Al2O3 coatings were evaluated by Optical Emission Spectrometer (OES), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), ASTM D 3359-97, Metallurgical Microscope (ASM standards) and ASTM B117-07 standards.