Application of vapor-deposited carbon and zinc as a substitute for palladium catalyst in the electroless plating of nickel

A new electroless nickel plating technique is described which eliminates the conventional use of palladium catalyst. Using a physical vapor deposition technique, layers of carbon and of zinc of approximately 10 and 20 nm thickness, respectively, were deposited onto an ABS resin substrate on which had previously been adsorbed a colloidal mixed hydroxide containing nickel ions and copper ions. The electrons released by the oxidative dissolution of the zinc layer into the plating solution were utilized to reduce the colloids to metallic nickel and copper, which served as an anchor for the subsequently plated nickel films. The peeling strengths of the electroless nickel films resulting from the application of this technique were in the order of 200 kg/m, in contrast to values of approximately 220 kg/m obtained using a conventional tin (2+) sensitizer and palladium (2+) activator.