The Influence of Unsaturated Organic Molecules in the Electrocrystallization of Nickel

Abstract

The fiber textures of nickel electrodeposits grown in the presence of unsaturated organic compounds are studied by x‐ray diffraction and shown to be related to the nature of the unsaturation present in the molecule. The structural environment of this unsaturation influences the magnitude of the additive activity. A number of compounds with an ethylenic unsaturation were extensively studied. The [110] axis fiber texture is then preferentially formed. In the presence of other compounds, e.g., acetylenic or aryl‐sulfonic compounds, the fiber texture is [100] or [211]. These modifications of crystal growth are interpreted by the adsorption‐hydrogenation‐desorption process. The nature of bonds between the metallic surface and the adsorbed molecule can differ according to the unsaturation, and so the quantity of adsorbed hydrogen atoms involved in the hydrogenation step.