Narrow Results

Different electroless Ni–P coatings were deposited on open-cell aluminum foams at various bath pH. The effect of bath pH on the morphology, structure, components, phases and corrosion resistance of the Ni–P coating was studied by scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), immersion test and electrochemical polarization measurement, respectively. The experimental results show that the bath pH not only changed the reactivity of the bath, but also had a influence on the microstructure and anticorrosive property of electroless Ni–P coating. The high pH bath raises the thickness of Ni–P coating but decreases the content of phosphorus element in the Ni–P coating. The corrosion resistance of the coated aluminum foams increases when the bath pH rises.

In this work, the primer-printed and then self-assembled poly(ethylene terephthalate) (PET) sheets were plated when the bath pH increased from 7 to 11. The effects of bath pH on the structural and electrical properties of electroless nickel plating were investigated systematically using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the crystallographic structures of Ni-plated PET (NPP) sheets were face centered cubic, the preferential orientation of the coatings changes from (200) plane to (111) plane, the growth rate of plated nickel coating increased from 3.71$\mu$m/min to 8.13$\mu$m/min, the average Ni crystal size was increased from 0.23$\mu$m to 0.92$\mu$m, the average EMI-SE of NPP sheets was increased from 37.2dB to 38.6dB and the surface electrical resistivity of NPP sheets was decreased from 6235ohm $\cdot$ cm to 0.03ohm $\cdot$ cm with the increase of bath pH. The changes in structural and electrical properties were most possibly due to the fact that the thickness of coating increased.