Preferred orientations in nickel electro-deposits: II. A consideration of the effect of deposition conditions on the textures developed

Abstract

The theory of texture development in nickel electro-deposits, proposed in Part 1 of this paper, is used here to explain the trends of texture changes which result from variations in nickel deposition conditions. Only the commonly-reported <210>, <100> and <110> orientations are considered. The occurrence of systematic texture changes (with increase of temperature and current density and with addition of oxidizing agents) is indicated in the experimental data of previous workers. It is suggested that an increase in bath temperature leads to a decrease in the average surface concentration of adsorbed hydrogen atoms, and thus to changes of textures towards free growth, i.e., <210> → <100> → <110>. This conclusion is completely in agreement with experiments conducted, at a pH less then 5. The slight free growth trend observed with an increase of current density is tentatively ascribed to differences in the-slopes of the free growth η- i curve for different singlecrystal faces of nickel. The addition of oxidizing agents — it is argued — reduces surface coverage and hence produces texture changes towards free growth. Some limitations of the present work are indicated.