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SM ISO690:2012 IVSHIN , Ya.. Electrochemical reactions in the process of mechanical plating. In: Materials Science and Condensed Matter Physics, Ed. 7, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, Editia 7, p. 298. |
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Materials Science and Condensed Matter Physics Editia 7, 2014 |
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Conferința "Materials Science and Condensed Matter Physics" 7, Chișinău, Moldova, 16-19 septembrie 2014 | ||||||
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Pag. 298-298 | ||||||
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Mechanical plating supposes intensive mechanical impact (attack) on the plating surface of an electrolyte, which contains fine powder and ions of the deposed metal. Such plating and processes of their deposition have certain advantages in comparison to traditional galvanic plating. It was found out that deposition of coating from solutions, which do not contain zinc powder, does not take place. But increase of the powder amount in an electrolyte to some limit results in the speeding up of coating growth. Dependence of coating deposition speed from concentration of zinc chloride at first grows, and then decreases. This dependence is symbate for such conductivity of solution. Speed of coverage deposition in sulfate of zinc solution is relatively low (about 1 - 2 micrometers in 10 minutes), but substantially increases if chloride of sodium is included to this solution [1]. The results gained allow creating picture of process mechanism. The difference of standard potentials of zinc and iron makes is nearly 0.3 V. Obviously, subpotential before phase zinc deposition plays important role during the first stage of zinc deposition on allogenic basis. Because contact of zinc powder with the surface of basis results in the change of its compromise potential to subzero side. Lets estimate dynamics of zinc deposition with help of the the equalization j = j0(exp(aanFh/RT) - exp(- aкnFh/RT)), where j0 is density of current of exchange; aa, aк - anodic and cathode coefficients of transfer; n - number of electrons, which are moved in a reaction; h - overstrain. The results of calculations are shown in the fig. Density of current of exchange for zinc in chloride solutions (0.3 A/сm2) is sufficiently (more than 10 times) higher than in sulfate electrolytes (0.01 A/сm2). This results in the different values of current density, while values of polarization are the same. Our research has shown, that speed of the mechanical plating e in analogical chloride and sulfate solutions corresponds to the value of cathode current density (0.2 and 0.007 A/сm2). This corresponds a value a cathode overstrain nearly 10 mV at the indicated values of kinetic parameters. |
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<?xml version='1.0' encoding='utf-8'?> <oai_dc:dc xmlns:dc='http://purl.org/dc/elements/1.1/' xmlns:oai_dc='http://www.openarchives.org/OAI/2.0/oai_dc/' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd'> <dc:creator>Ivşin, I.V.</dc:creator> <dc:date>2014</dc:date> <dc:description xml:lang='en'><p>Mechanical plating supposes intensive mechanical impact (attack) on the plating surface of an electrolyte, which contains fine powder and ions of the deposed metal. Such plating and processes of their deposition have certain advantages in comparison to traditional galvanic plating. It was found out that deposition of coating from solutions, which do not contain zinc powder, does not take place. But increase of the powder amount in an electrolyte to some limit results in the speeding up of coating growth. Dependence of coating deposition speed from concentration of zinc chloride at first grows, and then decreases. This dependence is symbate for such conductivity of solution. Speed of coverage deposition in sulfate of zinc solution is relatively low (about 1 - 2 micrometers in 10 minutes), but substantially increases if chloride of sodium is included to this solution [1]. The results gained allow creating picture of process mechanism. The difference of standard potentials of zinc and iron makes is nearly 0.3 V. Obviously, subpotential before phase zinc deposition plays important role during the first stage of zinc deposition on allogenic basis. Because contact of zinc powder with the surface of basis results in the change of its compromise potential to subzero side. Lets estimate dynamics of zinc deposition with help of the the equalization <strong>j = j<sub>0</sub>(exp(</strong><strong>a<sub>a</sub>nF</strong><strong>h/RT) - exp(- </strong><strong>a<sub>к</sub>nF</strong><strong>h/RT)),</strong> where <strong>j<sub>0</sub></strong> is density of current of exchange; a<sub>a</sub>, a<sub>к - </sub> anodic and cathode coefficients of transfer; n - number of electrons, which are moved in a reaction; h<strong> </strong> - overstrain. The results of calculations are shown in the fig. Density of current of exchange for zinc in chloride solutions (0.3 A/сm<sup>2</sup>) is sufficiently (more than 10 times) higher than in sulfate electrolytes (0.01 A/сm<sup>2</sup>). This results in the different values of current density, while values of polarization are the same. Our research has shown, that speed of the mechanical plating e in analogical chloride and sulfate solutions corresponds to the value of cathode current density (0.2 and 0.007 A/сm<sup>2</sup>). This corresponds a value a cathode overstrain nearly 10 mV at the indicated values of kinetic parameters.</p></dc:description> <dc:source>Materials Science and Condensed Matter Physics (Editia 7) 298-298</dc:source> <dc:title>Electrochemical reactions in the process of mechanical plating</dc:title> <dc:type>info:eu-repo/semantics/article</dc:type> </oai_dc:dc>