Abstract
Effect of the thiourea and its derivatives as well as some surfactants on the formation of bright copper deposits from copper sulfate bath has been studied.
Cathode polarization measurements were carried out in the presence of addition agents and the deposits obtained were analyzed by electron diffraction method and also by photomicroscopy in order to elucidate the characteristics of the crystal structure with respect to the formation of bright deposits.
Addition of brighteners, such as thiourea, acetyl thiourea, allyl thiourea and phenyl thiourea increase the cathode polarization and lead to smooth highly-reflecting surfaces. On the other hand, methyl iso-thiourea, hexamethylene di-thiourea and naphthyl thiourea is found to be ineffective in the formation of bright deposits and generally result in the lower cathode polarization.
Among the surfactants studied, only anionic surfactants, such as Sinto Rex L-100 and Rapisol-80 give the favorable influence on the formation of bright deposits.
It was found that there was no direct relationship between the degree or type of the preferred orientation and the brightness of the deposits.
