Near-surface solution pH measurements during the pitting corrosion of AISI 1020 steel using a ring-shaped sensor

Author(s)

da Silva, Marina Medina ; Mascaro, Lucia Helena ; Pereira, Ernesto Chaves ; Zimer, Alexsandro Mendes

• Document type: Journal article
• Source: JOURNAL OF ELECTROANALYTICAL CHEMISTRY; v. 780, p. 7-pg., 2016-11-01.

Abstract

This work presents the development and characterization of a ring-shaped sensor built around a steel sample (AISI 1020) to determine the near-surface solution pH (NSSpH) duringpitting corrosion. The pH sensor is constituted by a ring of IrOx, a material that is sensitive to pH changes, synthesized using the Pechini method on a glass tube with a gap of 1 mm between the pH. sensor (ring) and the metal sample (disc). The evolution of the corrosion process was also followed using a temporal series of micrographs with an optical microscope. At the same time, the sensor followed the NSSpH during the passivation of the metal, during the breakdown of the passive film, and during the pit evolution in an aqueous basic solution containing HCO3- and Cl- species. When the pit potential was reached, the NSSpH was reduced by one pH unit. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 11/19430-0 - In situ investigation of carbon steel corrosion by means of temporal series micrographs coupled with electrochemical techniques
• Grantee: Alexsandro Mendes Zimer
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/13503-0 - Development of sensor for interfacial-pH analysis during the pit corrosion observed in situ by temporal series micrographs
• Grantee: Marina Medina da Silva
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC