Electroless Nickel Plating and Its Applications

ABSTRACT

Following the method of Brenner and Riddell, an ‘electroless’ technique has been developed for the deposition of nickel in this laboratory. In this technique a nickel salt is reduced on the surface being coated, usually iron or steel, by sodium hypophosphite. In contrast with displacement plating, the surface itself does not enter directly into the reaction. Under proper conditions, nickel is an effective catalyst for the reduction and this auto-catalytic effect permits the formation of coatings several mils thick, provided the hypophosphite and nickel salt in the bath are periodically replenished. Rates of deposition as high as 0·008 in. per hour have been obtained. The deposition can be made on both metals and insulators. Electroless nickel is superior in several respects to the conventional electro-deposit and, in addition, has the distinct advantage that the deposit is uniform in thickness on all surfaces to which the solution is freely accessible.

A brief report is given here of the mechanism of the process, the conditions for obtaining maximum deposition rate, the characteristics of the deposit and the variety of applications the technique has found.