MORPHOLOGY CHARACTERIZATION OF TIN
SURFACE IN THE PRESENCE OF
MICROORGANISMS BY SCANNING ELECTRON
MICROSCOPY (SEM) AND OTHERS TECHNIQUES
Guedes, J. A. C. Gondim, T. A. Filho, M. A. N. S. A. Pereira, W. G. Abreu, F. D. Magalhães,
C. E. C. and Silva R. C. B.
Universidade Estadual do Ceará, Campus Itaperi, CE, Brazil
Tin is one of the metals of great use in the electroplating industry. However, few studies have
been directed to investigate the behavior of the metal front of the presence of microorganisms.
Thus, this work reports the investigation of the corrosion of tin in neutral media in the
presence of bacteria Pseudomonas aeruginosa and Staphylococcus aureus. For this purpose,
immersion test with weight loss associated with scanning electron microscopy and X-ray
dispersive energy analysis spectroscopy techniques were conducted. Also, atomic absorption
spectrometry technique was used and pH measurements were performed. Metallic tin samples
with 1cm2-geometric area were treated with anhydrous ethyl alcohol, and then was immersed
in solution. The solution composition was NaCl 2g/L; NaH2PO4 0.05g/L; FeSO4 0.03g/L;
C12H22O11 0.03g/L; casein 0.03g/L and thiamine 0.01g/L. The strains of the bacteria
Pseudomonas aeruginosa ATCC27853 and Staphylococcus aureus ATCC25923 were kindly
provided by FIOCRUZ-RJ. It was found by the inoculation of bacteria into the solution for
their adaptation. It was possible to conclude that, in the presence and absence of the bacteria
Pseudomonas aeruginosa and Staphylococcus aureus, the tin surface does not undergo
significant changes on the morphology when comparing the tin surface into aseptic solution.
After 45 days- immersion time into the solution with Pseudomonas aeruginosa, it was
observed the discrete insoluble precipitates formation on the metal surface. The pH tends to
be moderately basic (in the presence of bacteria), whereas in the absence tends to be strongly
basic (pH = 9.4). Otherwise, it was found that biofilm formation occurs. Also, the bacteria
seem to influence the physicochemical characteristics of the solution.
Keywords: characterization, surface, tin, microorganisms.
Work supported by CNPq
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Email: [email protected]
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