XII Iberian Meeting of Electrochemistry XVI Meeting of the ...

XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PD 06
Corrosion behaviour of quaternary bronzes in slightly
passivating environments
Mariano Pérez, Maurizia Calvisi, Gemma Mª. González-Mesa
Departamento de Química Física. Universidad de La Laguna. Tenerife. España
mjperez@ull.es
This communication show the first results of a work on corrosion/protection
of bronze materials. This work has been developed from the factory ingots (first
foundry) of quaternary bronze materials and from the so called chimney residuals
resulting from a second cast bronze materials used for filling the sculpture molds.
The deviation of compositions and crystalline structure of both first and second foundry
bronzes have been studied by SEM/EDS and DRX and compared to the ingots factory
specifications.
Metal samples shaped as planar disks, as received from the factory (EB), were
kept in natural atmosphere, not specially corrosive (indoors), for 10-12 months. Then
they were characterized by SEM-EDX, noticing the topographic and composition
variations due to this oxidation period respect to their initial status.
Following the results of the previous observations the redox characterization
of these materials were carried out with the abovementioned shaped disk samples as
working electrodes, by cyclic voltammetry in a slightly passivating environment,
aqueous sodium tetraborate solution (pH 9.3), to detect components peaks in the records
made and trying to assign them to redox couples of the metal components of these
alloys.
In parallel, the same type of voltammetric records were carried out with metal
samples of the main alloy components, that is, the components of the studied quaternary
bronze alloys, namely, copper, tin, zinc and lead.
Correlation of redox characteristics and corrosion behaviour versus the
crystalline structure of these quaternary alloys are attempted [1].
Acknowledgments: enterprise and materials
supplier.2.SEM/EDS and XRD SEGAI Services from ULL. 3 Prof. L. Galindo. Depto. Quimica
Analítica. ULL.
References
[1]
September, 811, 2010. ISEL - Lisbon 88