ELECTROCHEMICAL BEHAVIOR OF COBALT IN PHOSPHORIC ACID.

To select a system of electrolytic polishing, the work investigated the electrochemical behavior of cobalt (electrolytic brand KO, purity 99. 98%) in solutions of phosphoric acid (10-50%) at room temperature. The results show that the polishing of cobalt in a galvanostatic system is impossible. After the application of the polishing current, the potential is displaced in the positive direction and, bypassing the region of polishing and the formation of the black oxide film, passes into the region of evolution of oxygen ( phi greater than equivalent to 1. 5 V). Here cobalt is not polished, in contrast to the polishing of carbon steel and copper, the polishing of which in phosphoric acid occurs with an evolution of oxygen. Thus, the electrolytic polishing of cobalt in phosphoric acid at room temperature can be accomplished only in a potentiostatic system within the potential range 0. 4-0. 7 V.