Electroless Nickel Plating on Magnesium Alloy

he inherent lightness and good strength-to-weight ratio of T magnesium has focused attention on increasing applications in aerospace and allied fields. Its density is two thirds that of aluminum-a conventional structure material for aerospace. Magnesium has one drawback: It is prone to atmospheric corrosion. Further, because of its high chemical affinity for aqueous solutions, it is categorized as a difficult metal for electrochemical treatments. The highly reactive nature of magnesium is clearly indicative by its position in the electromotive series (E" = -2.37 V). The situation is still more complex for magnesium alloys, where the alloying constituents introduce electrochemical heterogeneity. 1*2 Communication satellites make use of a traveling wave tube (TWT) for amplification of signals. In a TWT the collector is the main source of heat dissipation. The electrodes are heated by the residual kinetic energy of the collected electrons; however, the electrodes must be maintained at a relatively low temperature. There are two ways to dissipate this heat into cold space (see Fig. 1). 1. Heat conduction from the electrodes to the spacecraft radiator. This is called conduction cooling and is suit-