Ultrasensitive LPFG corrosion sensor with Fe-C coating electroplated on a Gr/AgNW film

Fan

Chen

2020

Sensors

Self Cite

In this study, graphene/silver nanowire (Gr/AgNW)-based, Fe-C coated long period fiber gratings (LPFG) sensors were tested up to 72 hours in 3.5 w.t% NaCl solution for corrosion-induced mass loss measurement under four strain levels: 0, 500, 1000 and 1500 µε. The crack and interfacial bonding behaviors of laminate Fe-C and Gr/AgNW layer structures were characterized using Scanning Electron Microscopy (SEM) and electrical resistance measurement. Both optical transmission spectra and electrical impedance spectroscopy (EIS) data were simultaneously measured from each sensor. Under increasing strains, transverse cracks appeared first and were followed by longitudinal cracks on the laminate layer structures. The spacing of transverse cracks and the length of longitudinal cracks were determined by the bond strength at the weak Fe-C and Gr/AgNW interface. During corrosion tests, the shift in resonant wavelength of the Fe-C coated LPFG sensors resulted from the effects of the Fe-C layer thinning and the NaCl solution penetration through cracks on the evanescent field surrounding the LPFG sensors. Compared with the zero-strained sensor, the strain-induced cracks on the laminate layer structures initially increased and then decreased the shift in resonant wavelength in two main stages of the Fe-C corrosion process. In each corrosion stage, the Fe-C mass loss was linearly related to the shift in resonant wavelength under zero strain and with the applied strain taken into account in general cases. The general correlation equation was validated at 700 and 1200 µε to a maximum error of 2.5% in comparison with 46.5% from the zero-strain correlation equation.

Section: Characterization Of the Crack Distribution On Fe-c Layermentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Corrosion-Induced Mass Loss Measurement under Strain Conditions through Gr/AgNW-Based, Fe-C Coated LPFG Sensors

Fan

Chen

2020

Sensors

Self Cite

“…It is well-known that it is very important to accurately detect pH in industrial production, disease diagnosis, crop growth, life sciences, environment and other fields. [1][2][3][4][5][6][7][8] For example, in the chemical industry, the pH value may be the key factor to affect the whole production process. Since identities and yields of products are dependent on pH, the pH value of most chemical reactions must be strictly controlled.…”

Section: Introductionmentioning

confidence: 99%

Voltammetrically Measuring pH of Strong Basic Solution on Au Electrode Modified with Ag₃PO₄ Shell@Ag Core Nanoparticles

Zheng

2020

ChemistrySelect

Precise determination of pH values of strong basic solution is appealing and challenging. Herein, a voltammetric method for measuring pH of strong basic solution was developed using Ag3PO4 shell@Ag core nanoparticles as a pH indicator. Ag nanoparticles (AgNPs) were electrodeposited on Au electrode surface and then were electrochemically oxidized to form Ag+. A layer of Ag3PO4 was in‐situ formed on the surface of AgNPs by precipitation with PO43− in solution. As an electroactive species, Ag3PO4 can undertake an electrochemical redox reaction and its reduction peak potential is linear with pH values of solution in the range of 10–14. The slope of the linear equation is about −0.0196, which is consistent with that calculated by the Nernst equation. The resultant AgNPs/Ag3PO4 modified electrode has been successfully applied in the determination of pH of strong basic solution. The proposed voltammetic method for measuring pH value overcomes the shortcoming of pH glass electrode under strong basic environments.

“…Those reported particles were connected with golden wires that maintained good electrical conductivity and showed highlights on soft wearable sensors [6]. Furthermore, Fe and its alloy-based particles were also appropriate for sensors for hydrogen gas detection [7], long-period fiber grating (LPFG) corrosion [8], and mining waste water and soil leachate detection [9].…”

Section: Introductionmentioning

confidence: 99%

Corrosion and Magnetization Analyses of Iron Encapsulated Aluminum Particles by Numerical Simulations

Sun

et al. 2019

Coatings

In this study, the effects of corrosion and magnetization on iron (Fe) encapsulated aluminum (Al) particles were uncovered through the assistance of molecular dynamic (MD) simulations and finite element analysis (FEA). The corrosion of metal particles with two phases was designed to be surrounded by O 2 or H 2 O molecules. Next, the magnetization was simulated to be under a constant magnetic field. According to the obtained results, a portion of O 2 molecules did not react with Fe atoms. They were actually adsorbed on the particle surface and the adsorption eventually reached a saturated state. However, the saturated effect did not appear to be due to the oxidation behavior of other O 2 molecules. Both oxidation and adsorption effects released pressure on Fe atoms and caused different extents of displacements. Next, a similar saturated effect was also observed for adsorbed H 2 O molecules. At the same time, other reacted H 2 O molecules produced a significant amount of OH − and caused charge transfer from Fe atoms. Additionally, the geometrical distribution of particles' magnetic flux density and magnetization intensity were also studied.