ANODIC-DISSOLUTION AND PASSIVATION OF NI IN ACID ORGANIC APROTIC-SOLVENTS

The dissolution and passivation of Ni in de-aerated acid solutions (0. 1 N H2SO4) of acetonitrile (ACN) and N-N-dimethylformamide (DMF) has b een studied hy d.c. and a.c. techniques. Results obtained indicated th at the anodic dissolution of Ni in solutions of ACN and DMF is affecte d by the adsorption of solvent at the metallic interface, while the pa ssivation process is affected by the water content. The minimum amount of water content to observe passivity in water ACN mixtures is 11% by weight; in water-DMF mixtures Ni does not passivate even in presence of high water content (up to 35% by weight).