Electrodeposition of metals and alloys—new results and perspectives

Winand, René

doi:10.1016/0013-4686(94)e0023-s

Cited by 247 publications

(121 citation statements)

References 26 publications

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“…The differences in morphologies of electrochemically obtained particles from the nitrate and ammonium electrolytes at the macro level can be explained as follows: The processes of Ag electrodeposition from the nitrate electrolytes belong to the fast electrochemical processes characterized by the high values of the exchange current density (j 0 → ∞, and j 0 >> j L , where j 0 is the exchange current density and j L is the limiting diffusion current density), low melting points, and the high overpotentials for hydrogen discharge [30,31]. Due to these characteristics, Ag is situated into the group of the normal metals, together with Pb, Sn, Cd, and Zn.…”

Section: Discussionmentioning

confidence: 99%

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

Avramović

Pavlović

Maksimović

et al. 2017

Metals

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Silver powders chemically synthesized by reduction with hydrazine and those produced by electrolysis from the basic (nitrate) and complex (ammonium) electrolytes were examined by X-ray diffraction (XRD) and scanning electron microscopic (SEM) analysis of the produced particles. Morphologies of the obtained particles were very different at the macro level. The needle-like dendrites, as well as the mixture of irregular and regular crystals, were formed from the nitrate electrolyte, while the highly-branched pine-like dendrites with clearly noticeable spherical grains were formed from the ammonium electrolyte. The agglomerates of spherical grains were formed by reduction with hydrazine. In the particles obtained from the nitrate electrolyte, Ag crystallites were strongly oriented in the (111) plane. Although morphologies of Ag particles were very different at the macro level, the similarity at the micro level was observed between chemically-synthesized particles and those obtained by electrolysis from the ammonium electrolyte. Both types of particles were constructed from the spherical grains. This similarity at the micro level was accompanied by the similar XRD patterns, which were very close to the Ag standard with a random orientation of Ag crystallites. For the first time, morphologies of powder particles were correlated with their crystal structure.

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Section: Discussionmentioning

confidence: 99%

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

Avramović

Pavlović

Maksimović

et al. 2017

Metals

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“…According to their general kinetic behaviour in aqueous solution, metals can be classified into three classes [2,3]. These classes are:…”

Section: Introductionmentioning

confidence: 99%

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

Nikolić

Živković²,

Jokić³

et al. 2014

Maced. J. Chem. Chem. Eng.

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The polarization and morphological characteristics of powder forms of the group of the intermediate metals were examined by the analysis of silver and copper electrodeposition processes at high overpotentials. The pine-like dendrites constructed from the corncob-like forms, which are very similar to each other, were obtained by electrodeposition of these metals at the overpotential belonging to the plateaus of the limiting diffusion current density. A completely different situation was observed by the electrodeposition of silver and copper at the overpotential outside the plateaus of the limiting diffusion current density in the zone with the fast increase in current density with the overpotential. Silver dendrites, which were very similar to silver and copper dendrites obtained inside the plateaus of the limiting diffusion current density, were obtained at the overpotential outside the plateau. Due to the lower overpotential for hydrogen evolution for copper, hydrogen produced during the copper electrodeposition process strongly affected the surface morphology of copper. The same shape polarization curves with completely different surface morphologies of Cu and Ag electrodeposited at overpotentials after the inflection point clearly indicate the importance of morphological analysis in the investigation of polarization characteristics of the electrodeposition systems. The role of hydrogen as a crucial parameter in the continuous change of copper surface morphology from dendrites to honeycomb-like structures was investigated in detail. On the basis of this analysis, the transitional character of the intermediate metals between the normal and inert metals was considered. The typical powder forms characterising electrodeposition of the intermediate metals were also defined and systematized.Keywords: electrodeposition; copper; silver; dendrite; hydrogen; pores; cauliflower-like forms СПОРЕДБА НА ПОЛАРИЗАЦИОНИТЕ И МОРФОЛОШКИТЕ КАРАКТЕРИСТИКИ НА ЕЛЕКТРОХЕМИСКИ СОЗДАДЕНИ ПРАШКОВИДНИ ОБЛИЦИ НА ИНТЕРМЕДИЈАРНИ МЕТАЛИПреку анализа на процесите на електродепозиција на сребро и бакар при високи пренапони беа испитувани и споредувани поларизационите и морфолошките карактеристики на прашоци од интермедијарни метали. При електродепозиција на овие метали со пренапони што припаѓаат на платото на гранична дифузиона густина на струјата, беа добиени дендрити во вид на бор изградени од елементи слични на кочан од пченка, кои се многу слични еден на друг. Наполно поинаква состојба беше утврдена при електродепозиција на овие метали со пренапони надвор од платото на гранична дифузиона густина на струја во делот на брз пораст на густината на струјата. Дендрити на среброто, многу слични на оние на дендритите на сребро и бакар добиени при пренапони што припаѓаат на платото на гранична дифузиона густина на струјата, беа добиени при пренапони надвор од оние на платото. Поради помалиот пренапон за издвојување на водород врз бакар, водородот создаден врз овој метал нагласено ја менуваше морфологијата на површината на бакарот. Истиот облик на п...

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“…A partir de então, em função das crescentes exigências e regulamentações governamentais, tem-se procurado substituir estes banhos por alternativas capazes de minimizar os impactos ambientais 2,3 . Entretanto, apesar dos riscos de acidentes envolvidos no manejo do banho cianídrico e dos imensos danos ambientais causados pelos resíduos industriais produzidos 4,5 , ainda é muito comum a utilização destes nas indústrias galvânicas, motivada principalmente pelo baixo custo operacional quando comparados aos processos isentos de cianetos.…”

Section: Introductionunclassified

“…Por outro lado, já existem banhos alcalinos de zinco comerciais livres de cianeto. Entretanto, estes fazem uso de elevada carga de aditivação 5,12 , em substituição ao cianeto, aumentando significativamente os custos de montagem e manutenção [13][14][15] .…”

Section: Introductionunclassified

Estudo eletroquímico de um novo banho galvânico de zinco alcalino livre de cianetos

Silva¹,

Freire²,

Matos³

et al. 2006

Quím. Nova

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Federal do Ceará, CP 6035, 60455-970 Fortaleza -CE Recebido em 6/8/04; aceito em 8/4/05; publicado na web em 10/8/05 ELECTROCHEMICAL STUDY OF A NOVEL CYANIDE FREE GALVANIC PLATING SOLUTION OF ALKALINE ZINC. A systematic electrochemical study of a novel cyanide free galvanic plating solution of alkaline zinc is presented. Cell Hull tests and potentiodynamic linear polarization measurements were carried out to evaluate the influence of operational parameters, such as concentration, current efficiency and degradation of additives. The stability of the bath was assessed by a long term test during 40 h at 200 A m -2 . The morphology of the coatings was characterized by scanning electron microscopy. The results showed good performance of the plating solution. The cost is similar to that of the commercial cyanide bath and lower than that of the commercial cyanide free bath.Keywords: zinc plating; electrodeposition; cyanide free. INTRODUÇÃOO zinco é um dos metais mais utilizados industrialmente como revestimento anticorrosivo de materiais ferrosos por apresentar bom desempenho à exposição atmosférica, oferecendo proteção galvânica ao aço, mesmo em regiões de descontinuidades da camada. Adicionalmente, o processo galvânico de obtenção desta camada é relativamente barato quando comparado a outros revestimentos 1 .Até o início da década de 90, a maioria dos processos de obtenção galvânica dos revestimentos de zinco fazia uso de banhos alcalinos contendo cianetos. A partir de então, em função das crescentes exigências e regulamentações governamentais, tem-se procurado substituir estes banhos por alternativas capazes de minimizar os impactos ambientais 2,3 . Entretanto, apesar dos riscos de acidentes envolvidos no manejo do banho cianídrico e dos imensos danos ambientais causados pelos resíduos industriais produzidos 4,5 , ainda é muito comum a utilização destes nas indústrias galvânicas, motivada principalmente pelo baixo custo operacional quando comparados aos processos isentos de cianetos.Adicionalmente, os processos cianídricos apresentam outras características importantíssimas para a indústria, tais como elevada taxa de reposição metálica, pré-tratamento simples do metal base, facilidade de controle do processo, utilização de equipamentos pouco sofisticados, uniformidade e ductilidade do depósito 6 . Assim, o grande desafio atual neste campo consiste na substituição do banho cianídrico por processos preferencialmente alcalinos, competitivos em custo e qualidade, uma vez que os processos áci-dos à base de cloretos e sulfatos são muito sensíveis às contaminações orgânicas e metálicas, são altamente corrosivos e requerem instalações mais sofisticadas 7 .Adicionalmente, tem sido relatado na literatura o estudo de eletrólitos alternativos para deposição de zinco em banhos livres de cianeto, usando complexantes orgânicos: etanolamina 8 , acetatos 9 , poliaminas alifáticas quarternárias 10 , trietanolamina 11 e furfural aldeído 11 . Por outro lado, já existem banhos alcalinos de zinco comerciais livres de cianeto. Entretanto, ...

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Electrodeposition of metals and alloys—new results and perspectives

Cited by 247 publications

References 26 publications

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

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

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

Estudo eletroquímico de um novo banho galvânico de zinco alcalino livre de cianetos

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