FLUORINE-PASSIVATED ELECTROLESS NI-P FILMS

An optimal nickel difluoride (NiF2) film-formation technology has been investigated for electroless Ni-P deposited films, where highly sensi tive electrochemical anodic polarization measurement and thin-film x-r ay diffraction (XRD) amorphous structure as deposited which is convert ed into crystalline structure such as nickel phosphides (Ni2P or Ni3P) with heating, this is undesirable for the formation of homogeneous fl uorine passivation films. Low incident angle XRD allows us to determin e the fluoridation conditions where the NiF2 films little include thes e nickel phosphides crystals. Further, anodic polarization measurement curves support the film-formation conditions (temperature, fluorine c oncentration) of nickel difluoride and the effect of heat-treatment af ter fluoridation. The low fluoridation temperature at ca. 300-degrees- C is not sufficient and low fluorine concentration is also unfavorable for the fluoridation of the electroless Ni-P deposited films. We cond ucted several evaluations such as corrosion resistance, outgassing cha racteristics, and plasma resistance using the nickel difluoride films formed by the most favourable condition.