The Influences of Organic Additives on Zinc Electrocrystallization from KCl Solutions

Abstract

The effects of some conventional additives such as triton X‐10 (TX‐10), sodium methylene bis(naphthalene sulfonate) (NNO), phenylbenzylketone (PBK), and a CH‐1 brightener on the electrodeposition of zinc onto the glassy carbon electrode were examined using chronoamperometry. The surface morphology, grain size, and texture of the deposits were characterized by scanning electron microscope, transmission electron microscope, and X‐ray diffraction. It was found that the electrocrystallization mechanisms of zinc and microstructure of deposits are sensitive to the identity of organic additives. On one hand, in the absence of additive or in the presence of NNO or PBK, zinc deposition proceeds by three‐dimensional instantaneous nucleation and growth, while in the presence of TX‐10 or a CH‐1 brightener, zinc deposition follows the three‐dimensional progressive nucleation and growth. On the other hand, in the absence of additive, the deposit forms a loose and porous structure with no texture. In the presence of PBK and TX‐10, the deposits are (101) and (110) texture, respectively. And in the presence of a CH‐1 brightener, deposit is smooth and bright and forms a (101) and (110) texture, where a homogeneous distribution of small 8 nm grains appears. These facts show that the effects of a CH‐1 brightener on the zinc electrodeposition mainly result from the combinational action of TX‐10 and PBK. In addition, we also found that surface morphology of deposits is strongly correlated to deposit texture. © 1999 The Electrochemical Society. All rights reserved.