Evaluation of ZrO2–24MgO ceramic coating by eddy current method

Khan, A. Nusair; Khan, Sohaib Z.; Ali, Farhad; Iqbal, Muhammad Azhar

doi:10.1016/j.commatsci.2008.07.021

Cited by 19 publications

(3 citation statements)

References 15 publications

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“…ECT works on the principle of Faraday's law. It detects variations in coil impedance in the same exciter coil or voltage change in a separate coil [40]. When the exciter coil is placed on different materials, the coil impedance or voltage change in the receiver coil varies due to the changes in electrical resistivity and magnetic permeability of the materials [41].…”

Section: Mechanism Of Eddy Current Testingmentioning

confidence: 99%

Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

Guo

Ren

Zhang

2021

Chin. J. Mech. Eng.

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New materials and manufacturing technologies require applicable non-destructive techniques for quality assurance so as to achieve better performance. This study comprehensively investigated the effect of influencing factors including excitation frequency, lift-off distance, defect depth and size, residual heat, and surface roughness on the defect EC signals of an Inconel 738LC alloy produced by selective laser melting (SLM). The experimental investigations recorded the impedance amplitude and phase angle of EC signals for each defect to explore the feasibility of detecting subsurface defects by merely analyzing these two key indicators. Overall, this study revealed preliminary qualitative and roughly quantitative relationships between influencing factors and corresponding EC signals, which provided a practical reference on how to quantitively inspect subsurface defects using eddy current testing (ECT) on SLMed parts, and also made solid progress toward on-line ECT in additive/subtractive hybrid manufacturing (ASHM) for fabricating SLMed parts with enhanced quality and better performance.

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Section: Mechanism Of Eddy Current Testingmentioning

confidence: 99%

Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

Guo

Ren

Zhang

2021

Chin. J. Mech. Eng.

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“…The percentage of NiO phase increases linearly with time at any particular temperature. Since NiO has a magnetic permeability greater than one [17], therefore, it can be expected that the eddy current values will also increase linearly. However, it was observed that the eddy currents followed almost the same curve as in case of stresses measured after different intervals, Fig.…”

Section: Non Destructive Evaluationmentioning

confidence: 99%

Archives of Metallurgy and Materials

Mehmood

Rafiq

Durrani

et al. 2018

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Ni 3 Al coatings were obtained on AISI 321 steel samples by air plasma spraying system. The behavior of heat treatment on intermetallic coatings were evaluated after exposure at various temperatures i.e. 500ºC to 800ºC. The stay time in this regard was varied from 10 to 100 hours. The coatings were then characterized by X-Ray diffraction analysis, optical and scanning electron microscopy, eddy current measurements and stress analysis. It was observed that the formation of NiO increases drastically with time and temperature. The hardness of the coating increases with the formation of NiO. It was noted that the residual stresses can be correlated with the formation of NiO. Further, the development of residual stresses can be monitored by a non-destructive technique i.e. eddy current method.

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“…Research on nondestructive evaluation of thin films and coatings is an important research direction in the field of nondestructive testing, a series of progress has been made in recent years, and a variety of nondestructive testing techniques, such as fluorescence spectrum [10][11][12], X-ray [13,14], infrared [15,16], acoustic emission [17,18], eddy current [19,20], and ultrasonic [21,22], have been developed to evaluate the thin films and coatings. Nevertheless, all these traditional nondestructive testing methods have their own weaknesses.…”

Section: Introductionmentioning

confidence: 99%

Novel Terahertz Nondestructive Method for Measuring the Thickness of Thin Oxide Scale Using Different Hybrid Machine Learning Models

Chen

et al. 2020

Coatings

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Effective control of the thickness of the hot-rolled oxide scale on the surface of the steel strip is very vital to ensure the surface quality of steel products. Hence, terahertz nondestructive technology was proposed to measure the thickness of thin oxide scale. The finite difference time domain (FDTD) numerical simulation method was employed to obtain the terahertz time-domain simulation data of oxide scale with various thickness (0–15 μm). Added Gaussian white noise with a Signal Nosie Reduction (SNR) of 10 dB was used when simulating real test signals, using four wavelet denoising methods to reduce noise and to compare their effectiveness. Two machine learning algorithms were adopted to set up models to achieve this goal, including the classical back-propagation (BP) neural network algorithm and the novel extreme learning machine (ELM) algorithm. The principal component analysis (PCA) algorithm and particle swarm optimization (PSO) algorithm were combined to reduce the dimensions of the terahertz time-domain data and improve the robustness of the machine learning model. It could be clearly seen that the novel hybrid PCA-PSO-ELM model possessed excellent prediction performance. Finally, this work proposed a novel, convenient, online, nondestructive, noncontact, safety and high-precision thin oxide scale thickness measuring method that could be employed to improve the surface quality of iron and steel products.

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Evaluation of ZrO2–24MgO ceramic coating by eddy current method

Cited by 19 publications

References 15 publications

Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

Archives of Metallurgy and Materials

Novel Terahertz Nondestructive Method for Measuring the Thickness of Thin Oxide Scale Using Different Hybrid Machine Learning Models

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