Autocatalytic Deposition of Pure Nickel Films Having Bright Surfaces and High Electrical Conductivity

抄録

A solution has been developed for autocatalytic (electroless) pure Ni plating using hydrazine as a reducing agent that has three desired characteristics: high stability, a high deposition rate, and high deposit brightness. The solution components are nickel acetate, hydrazine, ethylenediaminetetraacetic acid, lactic acid, and boric acid. Saccharin sodium and formaldehyde are used as additives in some cases. The deposition rate and surface morphology of the films change with the composition of the plating solution. The deposition rate reaches 3.0 nm s^-1. The brightness of the Ni films depends on the surface morphology. The reflectance of the deposited films at a wavelength of 550 nm changes from 0.6% (black) to 54%, the same level as autocatalytic Ni-P alloy films. The total impurity content (C, N, B and S) of the deposited Ni films is less than 0.4 mass%. The lowest value of the total content is 0.12 mass%. Electrical conductivity increases with purity and reaches 11.3 × 10⁶ S m^-1, which is equivalent to pure Ni foil with a purity of 99.7%. The deposition rate, surface morphology, brightness, and electrical conductivity of autocatalytic pure Ni films can be controlled by changing the composition of the plating solution.