Correlation between crystal orientation and morphology of silver powder particles obtained by different methods of synthesis and conditions of electrolysis

Abstract

Morphologies of silver powder particles obtained by chemical and electrochemical processes of synthesis were correlated with their crystal structure. Reduction with hydrazine was used for the synthesis of Ag powder by the chemical process. The different kinds of electrolytes (the nitrate and the ammonium ones), regimes of electrolysis (the galvanostatic and the potentiostatic ones) and overpotentials of the electrodeposition were used for production of Ag powders by electrolysis. Morphologies of synthesized particles strongly depended on the method of synthesis and conditions of electrolysis. Agglomerates of approximately spherical grains were formed with hydrazine as the reducing agent. In the dependence of conditions and regimes of electrolysis, various forms of dendritic particles, such as the needle-like, fern-like and pine-like dendrites, were formed. The preferred orientation of Ag particles changed from the strong (111) preferred orientation for the Ag particles obtained by the electrolysis from the nitrate electrolyte in the galvanostatic regime and at the overpotential outside plateau of the limiting diffusion current density to almost random oriented Ag crystallites for chemically synthesized particles and the pine-like particles obtained from the ammonium electrolyte by the galvanostatic and those produced by the potentiostatic regime outside plateau of the limiting diffusion current density.

Morfologije čestica praha srebra dobijene hemijskim i elektrohemijskim procesima sinteze su povezane sa njihovom kristalnom strukturom. Proces redukcije sa hidrazinom je bio korišćen za hemijsku sintezu praha srebra. Različite vrste elektrolita (nitratni i amonijačni), režimi elektrolize (galvanostatski i potenciostatski) i prenapetosti elektrohemijskog taloženja su korišćene za proizvodnju praha srebra elektrolizom. Aglomerati približno sferičnih zrna su bili formirani sa hidrazinom kao redukcionim sredstvom. U zavisnosti od uslova i režima elektrolize, različite forme dendritičnih čestica, kao što su igličasti dendriti i oni nalik paprati i boru, su bili formirani. Preferencijalna orijentacija čestica srebra se menjala od stroge (111) preferencijalne orijentacije za čestice dobijene elektrolizom iz nitratnog elektrolita galvanostatskim režimom i na prenapetosti izvan platoa granične difuzione gustine struje do skoro slučajno orijentisanih kristalita srebra kod hemijski sintetizovanih čestica i onih nalik boru dobijenih iz amonijačnog elektrolita galvanostatskim režimom i potenciostatskim režimom na prenapetosti izvan platoa granične difuzione gustine struje.