Textural modifications in nickel electrodeposition under pulse reserved current (EN)

Spyrellis, N (EN)

Kollia, C (EN)

Nickel electrodeposits consists of crystallites whose orientation, microstructure and size depend on the electrolytic conditions. Study of the mechanism of nickel electrocrystallization has indicated that the oriented growth observed is determined by the specific inhibition exerted by the chemical species which exist or are formed on the metal-electrolyte interface (catholyte) and which are selectively absorbed on the continually renewed metal surface. The pulse reversed current (PRC) technique was used to perturb the electrocrystallization process and hence to change the texture and the structural characteristics of nickel electrodeposits. The strucrtural changes that occur in deposit orientation under PRC conditions were studied. Nickel electrodeposition was realized from a Watts-type bath on a rotated cathode, and the electrolysis parameters (current density, rotation velocity, electrolyte pH and temperature) were chosen in such a way that using direct current they led to the preparation of perfectly [100], [211], [210], [110]A and [110]B textured deposits. The deposit texture was determined by X-ray diffractometry and the results are summarized in texture diagrams given as a function of PRC parameters: pulse frequency and duty cycle. It was proved that the texture is directly related to PRC parameters, which provoke strong perturbation in the crystal growth process. This phenomenon is reinforced when both the pulse frequency and the duty cycle are small. The PRC technique affects the nickel electrocrystallization process according to a mechanism analogous to the action of organic additives under direct current conditions by intervening in the catholyte composition and hence in the adsorption-desorption phenomena occuring at the metal-solution interface during the dissolution and the deposition time. © 1993. (EN)

journalArticle (EN)

Crystal growth (EN)

Grain size and shape (EN)

Pulsed reversed current (PRC) technique (EN)

Composition (EN)

Crystal orientation (EN)

Electrocrystallization (EN)

Surfaces (EN)

Pulse frequency (EN)

Dissolution (EN)

Physics, Applied (EN)

Textures (EN)

Crystallites (EN)

Electrolysis (EN)

Nickel electrodeposits (EN)

Materials Science, Coatings & Films (EN)

Duty cycle (EN)

Watts type bath (EN)

Interfaces (materials) (EN)

Crystal microstructure (EN)

Electrolytes (EN)

Electrodeposition (EN)

Nickel (EN)

National Technical University of Athens

Digital Library of National Technical University of Athens | Dspace@NTUA

Κεντρική Βιβλιοθήκη Ε.Μ.Π.

Ιδρυματικό Αποθετήριο

Δημοσιεύσεις μελών Δ.Ε.Π. σε περιοδικά

Surface and Coatings Technology (EN)

English

1993 (EN)

http://hdl.handle.net/123456789/11088

1 (EN)

57 (EN)

71 (EN)

0257-8972 (EN)

ISI:A1993KZ83600010 (EN)

75 (EN)

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