金属-非金属複合電気めっき膜の金属基板界面における組成勾配 Compositional Gradient at the Interface of Metal-Nonmetal Composite Electroplating Films on Metal Substrates
Ultrahydrophobic composite films containing nickel and tetrafluoroethylene oligomers (TFEO) were formed on nickel plates by a composite electroplating method. The H<SUB>2</SUB>O contact angle increased with increasing electrical charge passed (Q), reaching a plateau of 142±2°once Q exceeded 2.4 C cm<SUP>-2</SUP>. From weight measurements and diffuse reflectance infrared spectra of films of varying thickness (d), the ratio of the surface amount of TFEO to that of nickel is revealed to increase gradually with increasing Q, when d<1.4 μm. The compositional gradient at the interface can be explained by the large difference between TFEO particles and Ni<SUP>2+</SUP> ions regarding the time each species attains a constant electrophoretic velocity. The time-lag mechanism further predicts that there is generally present such a compositional gradient at the interface between metal-nonmetal composite electro-plating films and substrates. Electron probe microanalysis and Auger electron spectroscopy indicated that the surface consists of a TFEO protrusive area (-60%) and a nickel-rich hollow area (-40%). The ultrahydrophobic character of the composite film is discussed on the basis of a two component heterogeneous surface model in which the incorporation of air into the Ni-rich hollow region is taken into account.
色材協會誌 71(3), 170-175, 1998-03-20