A time-dependent direct current potential drop method to evaluate thickness of an oxide layer formed naturally and thermally on a large surface of carbon steel

Ali, Md. Rostom; Saka, Masumi; Tohmyoh, Hironori

doi:10.1016/j.tsf.2012.10.089

Cited by 3 publications

(6 citation statements)

References 29 publications

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“…Ali et al discussed that the potential drop changes during the DCPD measurement is due to creep of the oxide film caused by Joule heat at the contact point (Ali, et al, 2010(Ali, et al, , 2012. In this study, the same tendencies of potential changes could be obtained in stainless steel, but they were not as clear as those Ali et al obtained from carbon steel (Ali, et al, 2010(Ali, et al, , 2012.…”

Section: Discussionsupporting

confidence: 65%

“…The DCPD measurement system of Ali et al (Ali, et al, 2010(Ali, et al, , 2012 was used to measure the oxide film of the carbon steel. Figure 1 schematically shows the layout of the measurement system.…”

Section: A Direct Current Potential Drop Measurementmentioning

confidence: 99%

“…1 Layout of the DCPD measurement system. A direct current is applied through outer probes, and the potential drop was measured between inner probes (Ali, et al, 2012) Four probes are made of SUS304 without gold plating at the tip.…”

Section: A Direct Current Potential Drop Measurementmentioning

confidence: 99%

“…If the thickness of the oxide film can be detected quantitatively and in-situ, one may be able to evaluate the possibility of SCC initiation and take preventive maintenance measures. Ali et al previously tried to measure the oxide film thickness of carbon steel formed in an atmosphere between room temperature to 292ºC (565K) using a four-point-probe direct current potential drop (DCPD) method (Ali, et al, 2010(Ali, et al, , 2012. They showed that the measured potential difference decreased in a constant current condition during acquisition time and finally the current became closer to the value of the non-oxide film condition.…”

Section: Introductionmentioning

confidence: 99%

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A direct current potential drop method for evaluating oxide film thickness formed in high-temperature water

Anzai

Ishibashi

Saka

2016

Mechanical Engineering Letters

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A direct current potential drop method for evaluating oxide film thickness formed in high-temperature water Abstract To establish an evaluation technique for oxide film thickness in-situ, the applicability of a four-point-probe direct current potential drop method is discussed in this study. Several samples of JIS SUS316L stainless steel with different oxide film thickness were prepared after immersing them in oxygenated pure water at 288ºC for different periods. The oxide film thickness was measured by cross sectional observation using a transmission electron microscope. Potential drop on the oxide surface was measured every second during an acquisition period of about 20 s while a constant current was being injected into the sample simultaneously. This kind of measurement was repeatedly carried out at several arbitrary contact positions on the surface of the same sample. The measurement results showed that the potential drop slightly changed during the acquisition period and the tendency varied at the different contact positions. Multiple measurements at different contact positions revealed that the tendency could be categorized into two general types: the decreasing potential drop and the increasing potential drop, defined by the overall trend of the potential drop during the acquisition time. It was found that the ratio of contact positions with a decreasing potential drop tendency to all the contact positions of measurement tended to increase as applied current increased. This tendency depended on the oxide film thickness. The threshold value of applied current was found to correlate well with the oxide film thickness when the occurrence rate of decreasing potential drop ranged from 70 to 90% showing the best correlation at 70%.

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Section: Discussionsupporting

confidence: 65%

Section: A Direct Current Potential Drop Measurementmentioning

confidence: 99%

Section: A Direct Current Potential Drop Measurementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A direct current potential drop method for evaluating oxide film thickness formed in high-temperature water

Anzai

Ishibashi

Saka

2016

Mechanical Engineering Letters

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“…The conductivity and thickness of the plate were 33.6 MS/m and 6 mm. It is noted that the plate conductivity was measured via the direct current potential drop method [ 25 , 26 ]. The profile and opening size of each corrosion are tabulated in Table 3 .…”

Section: Methodsmentioning

confidence: 99%

Imaging of Subsurface Corrosion Using Gradient-Field Pulsed Eddy Current Probes with Uniform Field Excitation

Ren

Yan

et al. 2017

Sensors

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A corrosive environment leaves in-service conductive structures prone to subsurface corrosion which poses a severe threat to the structural integrity. It is indispensable to detect and quantitatively evaluate subsurface corrosion via non-destructive evaluation techniques. Although the gradient-field pulsed eddy current technique (GPEC) has been found to be superior in the evaluation of corrosion in conductors, it suffers from a technical drawback resulting from the non-uniform field excited by the conventional pancake coil. In light of this, a new GPEC probe with uniform field excitation for the imaging of subsurface corrosion is proposed in this paper. The excited uniform field makes the GPEC signal correspond only to the field perturbation due to the presence of subsurface corrosion, which benefits the corrosion profiling and sizing. A 3D analytical model of GPEC is established to analyze the characteristics of the uniform field induced within a conductor. Following this, experiments regarding the imaging of subsurface corrosion via GPEC have been carried out. It has been found from the results that the proposed GPEC probe with uniform field excitation not only applies to the imaging of subsurface corrosion in conductive structures, but provides high-sensitivity imaging results regarding the corrosion profile and opening size.

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A Gradient-Field Pulsed Eddy Current Probe for Evaluation of Hidden Material Degradation in Conductive Structures Based on Lift-Off Invariance

Han

Abidin

et al. 2017

Sensors

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Coated conductive structures are widely adopted in such engineering fields as aerospace, nuclear energy, etc. The hostile and corrosive environment leaves in-service coated conductive structures vulnerable to Hidden Material Degradation (HMD) occurring under the protection coating. It is highly demanded that HMD can be non-intrusively assessed using non-destructive evaluation techniques. In light of the advantages of Gradient-field Pulsed Eddy Current technique (GPEC) over other non-destructive evaluation methods in corrosion evaluation, in this paper the GPEC probe for quantitative evaluation of HMD is intensively investigated. Closed-form expressions of GPEC responses to HMD are formulated via analytical modeling. The Lift-off Invariance (LOI) in GPEC signals, which makes the HMD evaluation immune to the variation in thickness of the protection coating, is introduced and analyzed through simulations involving HMD with variable depths and conductivities. A fast inverse method employing magnitude and time of the LOI point in GPEC signals for simultaneously evaluating the conductivity and thickness of HMD region is proposed, and subsequently verified by finite element modeling and experiments. It has been found from the results that along with the proposed inverse method the GPEC probe is applicable to evaluation of HMD in coated conductive structures without much loss in accuracy.

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A time-dependent direct current potential drop method to evaluate thickness of an oxide layer formed naturally and thermally on a large surface of carbon steel

Cited by 3 publications

References 29 publications

A direct current potential drop method for evaluating oxide film thickness formed in high-temperature water

A direct current potential drop method for evaluating oxide film thickness formed in high-temperature water

Imaging of Subsurface Corrosion Using Gradient-Field Pulsed Eddy Current Probes with Uniform Field Excitation

A Gradient-Field Pulsed Eddy Current Probe for Evaluation of Hidden Material Degradation in Conductive Structures Based on Lift-Off Invariance

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