Morphological and crystallographic characteristics of electrodeposited lead from a concentrated electrolyte

Abstract

Electrodeposition of lead from a concentrated nitrate solution was examined by scanning electron microscopy (SEM) and by X-ray diffraction (XRD) analysis of the obtained powder particles. Single crystals of the (111) preferred orientation were formed at a low overpotential by ohmic controlled electrodeposition. Irregular crystals, needle-like and fern-like dendrites, predominantly of the (111) preferred orientation, were formed at high overpotentials (the diffusion control of the electrodeposition). The ratio of Pb crystallites oriented in the (200), (220), (311) and (331) planes increased with increasing electrodeposition overpotential. The correlation between the morphologies and crystallographic structures of the lead deposits was discussed by the consideration of general characteristics of growth layers in electrodeposition processes.

Comparative analysis of the polarization and morphological characteristics of electrochemically produced powder forms of the intermediate metals

“…In the case of silver, the rapid increase in the current density with increasing overpotential is ascribed to the activation controlled electrodeposition at the tips of dendrites. This polarization behaviour for Ag is similar to the polarization characteristics of the normal metals (the high j 0 , the high hydrogen overpotential) [41,42]. In the case of copper, the fast growth of the current density after the inflection point is due to competition between the hydrogen evolution reaction and the copper electrodeposition process.…”

Comparative Morphological and Crystallographic Analysis of Electrochemically- and Chemically-Produced Silver Powder Particles

“…The different electrodeposition rate onto different crystal faces will cause a disappearance of fast-growing faces and a survival of slow-growing ones. The origin of Ag crystallites oriented in the (111) plane is of growth centers present in the interior of crystal faces [35,40], and this type of growth centers are denoted as "center type". On the other hand, the origin of Ag crystallites oriented in the (200), (220), and (311) planes is of growth centers present on the edges and corners of growing forms (as "edge and corner type") [35,40].…”

“…The origin of Ag crystallites oriented in the (111) plane is of growth centers present in the interior of crystal faces [35,40], and this type of growth centers are denoted as "center type". On the other hand, the origin of Ag crystallites oriented in the (200), (220), and (311) planes is of growth centers present on the edges and corners of growing forms (as "edge and corner type") [35,40]. The current densities responsible for the crystal growth based on growth centers of "edge and corner type" are higher than those responsible for crystal growth based on growth centers of "center type".…”

Fundamental aspects of lead electrodeposition processes: Nucleation and growth

“…Oblik ovih čestica istrajava tokom taloženja u omskoj kontroli (slika 7a), dok one bivaju transformisane tokom mešovite omsko-difuzione ili pune difuzione kontrole u različite nepravilne forme koje se često označavaju prekursorima dendrita (slika 7b), ili u dendrite različite forme i tipa (slika 7c) [24].…”

“…Rentgensko-difrakciona analiza olovnih taloga je pokazala da bez obzira na tip elektrolita i uslove elektrohemijskog taloženja, u svim gore pokazanim i analiziranim morfološkim formama, kristaliti olova su bili dominantno orijentisani u (111) ravni [17,24,28,29]. Prisustvo kristalita orijentisanih u ostalim ravnima karakterističnih za ovaj tip kristalne rešetke, kao što su (200), (220), (311) i (331) ravan, je bilo primetno manje nego u (111) ravni.…”