EXAFS AND XRD STUDIES OF ‘ZN-CO’ ALLOY ELECTRODEPOSITS

EXAFS AND XRD STUDIES OF ‘ZN-CO’ ALLOY ELECTRODEPOSITS

CARPENTER, D. E. O. S.; CARPENTER, S. D.

Artigo:

The sacrificial behaviour of electrodeposited zinc layer on the surface of a ferrous alloy to delay the onset of ferrous corrosion is very well documented in the literature. However zinc-cobalt alloys show a marked improvement in the corrosion protection of a ferrous substrate in comparison with pure zinc layers. A protective layer of zinc-cobalt can be applied by means of simultaneous electro-deposition. The electro-deposited structure of a zinc-cobalt alloy was studied using X-Ray Diffraction (XRD) and Extended X-ray Absorption Fine Structure (EXAFS). The morphology of the electro-deposit was found to be significantly dependant on cobalt concentration of the electrolyte. Dilute electrolytes were found to yield a single phase hexagonal close packed (hcp) deposit similar to that of the constituent metals themselves. However electro-deposits formed under the same condition from electrolytes of higher cobalt concentration were found to contain a fine dispersion of an intermetallic phase identified as ‘Co5Zn21’.

The sacrificial behaviour of electrodeposited zinc layer on the surface of a ferrous alloy to delay the onset of ferrous corrosion is very well documented in the literature. However zinc-cobalt alloys show a marked improvement in the corrosion protection of a ferrous substrate in comparison with pure zinc layers. A protective layer of zinc-cobalt can be applied by means of simultaneous electro-deposition. The electro-deposited structure of a zinc-cobalt alloy was studied using X-Ray Diffraction (XRD) and Extended X-ray Absorption Fine Structure (EXAFS). The morphology of the electro-deposit was found to be significantly dependant on cobalt concentration of the electrolyte. Dilute electrolytes were found to yield a single phase hexagonal close packed (hcp) deposit similar to that of the constituent metals themselves. However electro-deposits formed under the same condition from electrolytes of higher cobalt concentration were found to contain a fine dispersion of an intermetallic phase identified as ‘Co5Zn21’.

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DOI: 10.5151/chemeng-cobeq2014-0136-26873-182153

Referências bibliográficas

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Como citar:

CARPENTER, D. E. O. S.; CARPENTER, S. D.; "EXAFS AND XRD STUDIES OF ‘ZN-CO’ ALLOY ELECTRODEPOSITS", p-13213-13221. In: Anais do XX Congresso Brasileiro de Engenharia Química - COBEQ 2014 [= Blucher Chemical Engineering Proceedings, v.1, n.2]. São Paulo: Blucher, 2015.
ISSN 23591757, DOI 10.5151/chemeng-cobeq2014-0136-26873-182153