Effects of Complex Agents and pH on the Deposition Behavior of Electroless Ni-Co-P Film

Electroless plated Ni-Co-P films have been used to suppress the electromagnetic waves from magnetic recording media, and the suppression is known to be achieved with films made with optimized plating composition and plating condition. Effects of complexing agents on the deposition rate and bath stability of Ni-Co-P film were studied using sodium citrate, sodium tartrate and multi-complex agents containing both of them. Deposition of electroless Ni-Co-P platings was dependent upon the complexing agents. Deposition rate was twice when using sodium tartrate compared to that using sodium citrate. And it was slightly slower with multi-complex agents than with sodium tartrate, bath stability being declined in the former. Deposition rate increased with increasing pH until pH 11. Excellent bath stability and good deposition rate were obtained using multi-complex agent as sodium citrate 0.10 mol/L and sodium tartrate 0.15 mol/L in the electroless Ni-Co-P plating films.