Patterned Ni-P alloy films prepared by "reducing-discharging" process and the hydrophobic property

Patterned hydrophobic Ni-P alloy films consisting of orderly and regular micro-nanoscale particles were fabricated through the synergistic effect of electrochemical deposition and chemical deposition. Ni-P alloy films were deposited for different times and characterized by scanning electron microscope (SEM). It was confirmed that the addition of reducing agent induced the formation of nanoscale particles, in contrast with pure Ni film deposited by single electrochemical deposition. As "point-discharge effect", the current density was higher at the edge of the nanoscale particles, and Ni ions would be deposited at the particles through the "point-discharge effect". Then the Ni-P alloy films grew by "reducing-discharging" process. The X-ray photoelectron spectroscopy (XPS) was used to detect the composition and valence states of these alloy films. The existence of oxidation state of element P in these films corresponding to that in H2PO3(-), also gave direct evidence for the occurrence of chemical deposition, during the electrochemical deposition process. The prolongation of deposition time could provide more time for the patterned morphology to grow up. The surface roughness, evaluated by surface profilometer, increased as the deposition time extension. And these films showed gradually increased hydrophobic properties with the increase in deposition time.