Development of sensor for interfacial-pH analysis during the pit corrosion observed in situ by temporal series micrographs

• Grant number: 13/13503-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2013
• End date: November 30, 2016
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Lucia Helena Mascaro Sales
• Grantee: Marina Medina da Silva
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The project target is the study of interfacial pH changes during the pitting corrosion of AISI 1040 steel through time series micrographs, with an optical microscope, and employing a rotating ring-disk electrode. For this last one, will be develop a rotational pH electrode where the metallic material under investigation will be the disk of electrode, and the ring will be of IrO2, a sensitive material to pH changes. Polarizing the disc on the pitting potential, Epit, interfacial pH changes during the pitting corrosion of metal will be monitored and quantified in the ring. Furthermore, the investigation of the steel corrosion will be made by measurements of open circuit potential, Eoc, and polarization curves, PC, in order to determine the Epit to the experimental condition under study. These techniques will be used to study the corrosion in aqueous solution containing carbonate and chloride ions. The effect of chloride concentration during the interfacial pH change, the effect of pH indicator added in the solution, and the effect of filters, will be investigated to make better the pitting visualization,. Finally, using the time series micrographs, the pitting initiation, progression and passivation, will be studied through of color changes in the solution around the pit and through the interfacial pH data obtained with the rotating ring-disk electrode.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DA SILVA, MARINA MEDINA; MASCARO, LUCIA HELENA; PEREIRA, ERNESTO CHAVES; ZIMER, ALEXSANDRO MENDES. Near-surface solution pH measurements during the pitting corrosion of AISI 1020 steel using a ring-shaped sensor. Journal of Electroanalytical Chemistry, v. 780, p. 379-385, NOV 1 2016. (13/13503-0, 13/07296-2, 11/19430-0)

ZIMER, ALEXSANDRO MENDES; DA SILVA, MARINA MEDINA; MACHADO, EDUARDO G.; VARELA, HAMILTON; MASCARO, LUCIA HELENA; PEREIRA, ERNESTO CHAVES. Development of a versatile rotating ring-disc electrode for in situ pH measurements. Analytica Chimica Acta, v. 897, p. 17-23, OCT 15 2015. (13/16930-7, 13/13503-0, 12/07313-1, 11/19430-0, 13/07296-2)

DA SILVA, MARINA MEDINA; MASCARO, LUCIA HELENA; PEREIRA, ERNESTO CHAVES; ZIMER, ALEXSANDRO MENDES. Near-surface solution pH measurements during the pitting corrosion of AISI 1020 steel using a ring-shaped sensor. JOURNAL OF ELECTROANALYTICAL CHEMISTRY, v. 780, p. 7-pg., 2016-11-01. (11/19430-0, 13/13503-0, 13/07296-2)