The determination of coating performance with impedance measurements—II. Water uptake of coatings

Westing, E.P.M. van; Ferrari, G.; Wit, J.H.W. de

doi:10.1016/0010-938x(94)90197-x

Cited by 230 publications

(74 citation statements)

References 22 publications

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“…Therefore water uptake has been substantially studied. [51][52][53][54] The variation of coating capacitance C c with the amount of water is typically expressed as applicable for a plate capacitor 51,53,55…”

Section: E Electrochemical Characterizationmentioning

confidence: 99%

Waterborne chitosan–epoxysilane hybrid pretreatments for corrosion protection of zinc

Fernández-Solis

Erbe

2016

Biointerphases

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Biopolymer-based systems are extensively studied as green alternatives for traditional polymer coatings, e.g. in corrosion protection. Chitosan-epoxysilane hybrid films are presented in this work as a chitosan-based protective system, which could e.g. be applied in a pretreatment step. For the preparation of the chitosan-epoxysilane hybrid systems, a sol-gel procedure was applied. The function of the silane is to ensure adhesion to the substrate. On zinc substrates, homogeneous thin films with thickness of 50 − 70 nm were obtained after thermal curing. The hybrid-coated zinc substrates were characterized by infrared (IR) spectroscopy, ellipsometry and X-ray photoelectron spectroscopy (XPS). As model corrosion experiments, linear polarization resistance was measured, and cathodic delamination of the weak polymer coating poly(vinylbutyral) [PVB] was studied using scanning Kelvin probe. Overall, chitosanepoxysilane hybrid pretreated samples showed lower delamination rates than unmodified chitosan coatings and pure PVB. Electrochemical impedance spectroscopy (EIS) confirmed a reduced ion permeability and water uptake by chitosan-epoxysilane films compared to that of a non-modified chitosan coating. Even though the coatings are hydrophobic and contain water, they slow down cathodic delamination by limiting ion transport.

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Section: E Electrochemical Characterizationmentioning

confidence: 99%

Waterborne chitosan–epoxysilane hybrid pretreatments for corrosion protection of zinc

Fernández-Solis

Erbe

2016

Biointerphases

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“…The Nyquist plots (Figure 4c), the Bode plots (Figure 5c), and the phase diagrams (Figure 5f) of the iETiO 2 (w) epoxy coating indicate its pure capacitive behavior over the entire 60-day immersion period. The barrier properties remained constant despite the phase angles starting to decrease at lower frequencies at 45 and 60 days, which implies that a small amount of water penetrated into the coating [36]. The EIS results show that the barrier property of iETiO 2 (w) epoxy coating is 20-50 times higher than that of the OTiO 2 (w) epoxy coating.…”

Section: Resultsmentioning

confidence: 65%

Anti-Corrosive and Scale Inhibiting Polymer-Based Functional Coating with Internal and External Regulation of TiO2 Whiskers

Wang

et al. 2018

Coatings

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Abstract:A novel multi-functional carrier of mesoporous titanium dioxide whiskers (TiO 2 (w)) modified by ethylenediamine tetra (methylene phosphonic acid) (EDTMPA) and imidazoline was devised in epoxy coating to improve the anti-corrosion and scale inhibition properties of metal surface. Rigorous characterization using analytical techniques showed that a mesoporous structure was developed on the TiO 2 (w). EDTMPA and imidazoline were successfully grafted on the outer and inner surfaces of mesoporous TiO 2 (w) to synthesize iETiO 2 (w). The results demonstrated that the corrosion resistance of the final iETiO 2 (w) epoxy coating is 40 times higher than that of the conventional unmodified OTiO 2 (w) epoxy coating. The enhanced corrosion resistance of the iETiO 2 (w) functional coating is due to the chelation of the scaling cations by EDTMPA and electron sharing between imidazoline and Fe. Scale formation on the iETiO 2 (w) coating is 35 times lower than that on the unmodified OTiO 2 (w) epoxy coating. In addition, EDTMPA and imidazoline act synergistically in promoting the barrier property of mesoporous TiO 2 (w) in epoxy coating. It is believed that this novel, simple, and inexpensive route for fabricating functional surface protective coatings on various metallic materials will have a wide range of practical applications.

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“…A value of 1 means that none of the dipoles are coupled. In this case, Equation (4) reduces to a CTRW-1 process, described according to Equation (1). Concerning this modification of the CTRW-2 you can fit the series measurements of coatings F and G too, without needing to introduce another relaxation theory.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…Therefore in the past in order to avoid problems caused by non-steady state behavior and drift, water uptake measurements using EIS were performed in a very restricted frequency range and interpretations were focused on the high frequency region only [1][2][3][4][5][6][7][8]. The limitation to the high frequency range leads automatically to a restriction of the information obtained from the series measurements.…”

Section: Introductionmentioning

confidence: 99%

The change of dielectric properties of barrier coatings during the initial state of immersion

Strunz¹,

Schiller²,

Vogelsang

2008

Materials & Corrosion

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The initial state of immersion of seven commercially available barrier coatings was monitored using electrochemical impedance spectroscopy (EIS). Within the first spectra, a fast change of state can be detected at low frequencies. This non-stationarity can be eliminated with an evaluation procedure, known as the Z-HIT algorithm, resulting in causal spectra which can be interpreted reliably and accurately. The spectra of the coatings can be well modeled by a parallel combination of a capacity and a two step continuous time random walk (CTRW-2) as a relaxation element. The capacity represents the pure dielectric properties of the coating material which are not affected by the penetrating electrolyte solution. This part of the evaluated coating capacity remains constant during the soaking. In contrast, the parameters of the CTRW-2 change during water uptake and can be attributed to pores and free sites within the coating material. This separation into parts which are affected by the penetrating solvent and parts which can be described by an ideal dielectric material reflects the inhomogeneous nature of the coatings under test.In the entire measured frequency range the change of the dielectric properties of the investigated systems can be modeled by the same equivalent circuit which was used formerly to interpret impedance spectra of barrier coatings in the saturated state, requiring four to five adjustable parameters for simulating the experimental data.

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The determination of coating performance with impedance measurements—II. Water uptake of coatings

Cited by 230 publications

References 22 publications

Waterborne chitosan–epoxysilane hybrid pretreatments for corrosion protection of zinc

Waterborne chitosan–epoxysilane hybrid pretreatments for corrosion protection of zinc

Anti-Corrosive and Scale Inhibiting Polymer-Based Functional Coating with Internal and External Regulation of TiO2 Whiskers

The change of dielectric properties of barrier coatings during the initial state of immersion

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