Embeddable Ag/AgCl sensors for in-situ monitoring chloride contents in concrete

Climent, M.Á.; Viqueira-Pérez, Estanislao; López-Atalaya, M.

doi:10.1016/0008-8846(96)00104-4

Cited by 72 publications

(58 citation statements)

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“…One of the most frequently used methods for Ag/ AgCl sensor preparation is anodization of Ag in a HCl solution [16][17][18][19]. The low pH of a HCl solution would limit the possible Ag 2 O formation [20,21] and would result in AgCl formation on the Ag substrate.…”

Section: Introductionmentioning

confidence: 99%

“…With anodization, the rate of AgCl formation depends on the applied current density and the time of the anodization [22]. Different current density and anodizing time have been reported for the preparation of sensors, e.g., 0.4 mA/cm 2 for 30 min [16,19], 2 mA/cm 2 for 30 min [17], 0.2 mA/cm 2 for 1 h [18], 0.4 mA/cm 2 for 2 h [3]. Logically, as with each electrochemical process of this kind, the anodization regime will affect the produced layer thickness, surface morphology and ionic/electron conductivity, respectively [5,10].…”

Section: Introductionmentioning

confidence: 99%

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Microstructure, surface chemistry and electrochemical response of Ag|AgCl sensors in alkaline media

et al. 2018

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Characterization of the Ag/AgCl electrode is a necessary step toward its application as a chloride sensor in a highly alkaline medium, such as concrete. The nucleation and growth of AgCl on Ag in 0.1 M HCl was verified through cyclic voltammetry. Ag anodization was performed at current densities, determined by potentiodynamic polarization in the same (0.1 M HCl) medium. The morphology and microstructure of the AgCl layers were evaluated via electron microscopy, while surface chemistry was studied through energy-dispersive spectroscopy and X-ray photoelectron spectroscopy. At current density above 2 mA/cm 2 , the thickness and heterogeneity of the AgCl layer increased. In this condition, small AgCl particles formed in the immediate vicinity of the Ag substrate, subsequently weakening the bond strength of the Ag/AgCl interface. Silver oxide-based or carbon-based impurities were present on the surface of the sensor in amounts proportional to the thickness and heterogeneity of the AgCl layer. It is concluded that a well-defined link exists between the properties of the AgCl layer, the applied current density and the recorded overpotential during Ag anodization. The results can be used as a recommendation for preparation of chloride sensors with stable performance in cementitious materials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure, surface chemistry and electrochemical response of Ag|AgCl sensors in alkaline media

et al. 2018

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“…and do not allow obtaining continuous information at an identical location over time [4,20,21]. Nondestructive techniques for chloride detection are therefore being developed [22][23][24][25][26][27][28]. Some of the proposed techniques are able to measure relative variations in local chloride contents rather than the absolute local chloride contents [26,28].…”

Section: Introductionmentioning

confidence: 99%

“…Potentiometric measurement of chloride with ISEs is a well-established method that has mostly been limited to laboratory conditions. However, some attempts of in situ use of Ag/AgCl ISE have been recently made for the specific case of concrete [22][23][24][25]27]. Nevertheless, surfaces of ISEs are notably sensitive to chemical species other than chloride [27,[34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Ag/AgCl ion-selective electrodes in neutral and alkaline environments containing interfering ions

et al. 2015

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Chloride ingress can lead to serious degradation of various materials and structures. Continuous measurements of local chloride concentrations is thus of uttermost importance for laboratory research, monitoring of structures, and predictions of the residual life span for the most common building materials. This work investigates the applicability of Ag/AgCl ion-selective electrodes for the non-destructive continuous measurement of local chloride concentrations in concrete and stone when exposed to chloride-bearing environments such as seawater. The work studies the stability of Ag/AgCl ion-selective electrodes in neutral and alkaline solutions and the sensitivity to the main interfering ions coming from the environment and from the material itself. The results indicate negligible interference from fluoride, sulfate, and hydroxyl but considerable from bromide and sulfide. In chloride-free alkaline solutions, Ag/ AgCl ion-selective electrodes are not stable over time, but-upon chloride arrival-they permit again reliable measurements of the chloride concentration. The results concerning interference are discussed by taking into account typical exposure environments and it is concluded that the ion-selective electrodes can satisfactorily be used to monitor chloride concentrations in built structures made out of concrete or stone.

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“…The potential of fabricated Ag probe coated with AgCl on its surface exhibits a linear relationship with the logarithm of chloride activity, 13,20,[22][23][24][25] which is widely used as a selective chloride electrode. The equilibrium at the surface is…”

Section: Effect Of CL − Concentrationmentioning

confidence: 99%

Electrochemical Characterization of a Solid Embeddable Ag/AgCl Reference Electrode for Corrosion Monitoring in Reinforced Concrete

Jin

Jiang

et al. 2014

Electrochemistry

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In this study, a new solid embeddable Ag/AgCl reference electrode (RE) was electrochemically investigated for corrosion monitoring in reinforced concrete. The electrode was fabricated by applying the cement mortar as the bottom layer, and the polymer gel as electrolyte. Several electrochemical methods were applied. The experiments were carried out in simulated concrete solutions and concrete. Furthermore, an exposure period over 1 year was used to evaluate the stability of the electrodes embedded in concrete. It has been found that the electrode potential was not obviously affected by the chloride concentration, but affected by the pH value of solution. The Ag/AgCl RE had uniformity in concrete environments. The reversibility of Ag/AgCl RE in all solutions is only within +4 mV. Besides, potentiodynamic tests revealed that the Ag/AgCl RE had a high exchange current density, which was advantageous when using Ag/AgCl RE to conduct resistance tests. Galvanostatic application of 0.2 µA/cm 2 caused little variation of potential with time (~30 mV in several days), indicating the presence of a finite polarization resistance. As a result, the new solid Ag/AgCl RE was suitable as a sensor electrode for concrete structures.

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Embeddable Ag/AgCl sensors for in-situ monitoring chloride contents in concrete

Cited by 72 publications

References 1 publication

Microstructure, surface chemistry and electrochemical response of Ag|AgCl sensors in alkaline media

Microstructure, surface chemistry and electrochemical response of Ag|AgCl sensors in alkaline media

Ag/AgCl ion-selective electrodes in neutral and alkaline environments containing interfering ions

Electrochemical Characterization of a Solid Embeddable Ag/AgCl Reference Electrode for Corrosion Monitoring in Reinforced Concrete

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