Estudo comparativo da corrosão em grades utilizadas em baterias de chumbo-ácido, formadas em processos de fundição e laminação.

Abstract

The quality of the grid of lead-acid batteries is one of the factors that most influence the durability of the product. Therefore, the technological evolution of batteries over time was mainly due to new forms of manufacturing alloys that compound the grids. This work has as main objective to conduct a study of the cathodic corrosion grid from different production technologies and assess the influence of lamination processing parameters on the quality of grid formed. This work was developed at the Federal University of Campina Grande in partnership with Moura factory batteries. The work consisted in testing the lead alloy used to manufacture the positive battery grids, with respect to its resistance to corrosion and check what conditions processing this alloy could improve the performance or not as corrosion. All samples studied in this work were subjected to the tests: corrosion potential versus time - EVT; Polarization resistance (Rp) and corrosion rate (CR); orrosimetry; Potentiodynamic curves - Pitting Potential; Cyclic potentiodynamic curves. SEM, Metallography and XRD were also performed on the samples. According to the results, we can conclude that: In the SEM images obtained for samples with modified speed lamination there was a gradual increase in surface roughness; when an increase in the speed of the laminating tape lead, an increase in etch rate thereof; The sample that underwent cooling prior to lamination got one of the lowest corrosion rates among the samples analyzed; The cast sample obtained a high corrosion rate compared to the laminated samples; XRD results confirmed the presence of the compounds identified in the reaction mechanisms discussed in the cyclic potentiodynamic test; By EVT testing was possible to verify that the increase in the tin content of the samples caused an improvement in corrosion resistance; In general, this work has shown that operating conditions in the processing and manufacture of battery grids would have a better or worse the corrosion resistance, so that the battery plant can manipulate the processing variables in order to obtain bars with improved corrosion resistance.