The structure of silver electrodeposited from the argentocyanide bath on to silver (110), (100) and (111) faces

Abstract

Electron diffraction is used to study systematically the surface structure of silver electro-deposited from the argentocyanide bath on electropolished (110), (100) and (111) faces of a silver single crystal. It is found that up to a certain critical current density (c.d.) the deposit structure continues the single-crystal lattice of the substrate up to large thicknesses, while the more this c.d. is exceeded, the more rapidly is twinned structure developed. At larger thicknesses again, this transition twinned zone gives place to a random polycrystalline region which only above about 70,000 Å deposit thickness develops into a preferred one-degree orientation characteristic of outward growth conditions. These new observations lead to a great clarification of the conditions of cathodic crystal growth. The dependence of the deposit structure on temperature and bath composition is also investigated. Optical microphotographs are also shown to illustrate the coarser details of the deposit surface form.