{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T19:59:27Z","timestamp":1760385567638,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2017,7,31]],"date-time":"2017-07-31T00:00:00Z","timestamp":1501459200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.3390\/s17081747","type":"journal-article","created":{"date-parts":[[2017,8,1]],"date-time":"2017-08-01T03:30:06Z","timestamp":1501558206000},"page":"1747","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Imaging of Subsurface Corrosion Using Gradient-Field Pulsed Eddy Current Probes with Uniform Field Excitation"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4257-2771","authenticated-orcid":false,"given":"Yong","family":"Li","sequence":"first","affiliation":[{"name":"State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center of NDT and Structural Integrity Evaluation, Xi\u2019an Jiaotong University, Xi\u2019an 710049, China"}]},{"given":"Shuting","family":"Ren","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center of NDT and Structural Integrity Evaluation, Xi\u2019an Jiaotong University, Xi\u2019an 710049, China"}]},{"given":"Bei","family":"Yan","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center of NDT and Structural Integrity Evaluation, Xi\u2019an Jiaotong University, Xi\u2019an 710049, China"}]},{"given":"Ilham","family":"Zainal Abidin","sequence":"additional","affiliation":[{"name":"Leading Edge NDT Technology (LENDT) Group, Malaysian Nuclear Agency, Bangi 43000, Kajang, Selangor, Malaysia"}]},{"given":"Yi","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center of NDT and Structural Integrity Evaluation, Xi\u2019an Jiaotong University, Xi\u2019an 710049, China"}]}],"member":"1968","published-online":{"date-parts":[[2017,7,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1016\/j.matdes.2015.08.053","article-title":"Effect of Corrosion Degradation on Failure Mechanisms of Aluminium\/Steel Clinched Joints","volume":"87","author":"Calabrese","year":"2015","journal-title":"Mater. Des."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1037","DOI":"10.1016\/j.apr.2016.06.007","article-title":"Role of Environmental Particulate Matters on Corrosion of Copper","volume":"7","author":"Saha","year":"2016","journal-title":"Atmos. Pollut. Res."},{"unstructured":"(2017, July 19). Trinity NDT. Available online: http:\/\/trinityndt.com\/.","key":"ref_3"},{"unstructured":"Xu, G.R., Guan, X.S., Qiao, Y.L., and Gao, Y. (2014, January 24\u201326). Analysis and Innovation for Penetrant Testing for Airplane Parts. Proceedings of the 2014 Asia-Pacific International Symposium on Aerospace Technology, Shanghai, China.","key":"ref_4"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2525","DOI":"10.3390\/s110302525","article-title":"Non-Destructive Techniques Based on Eddy Current Testing","volume":"11","author":"Javier","year":"2011","journal-title":"Sensors"},{"unstructured":"Singh, R. (2012). Applied Welding Engineering: Processes, Codes and Standards, Butterworth-Heinemann. [1st ed.].","key":"ref_6"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"319","DOI":"10.3233\/JAE-131681","article-title":"The Investigation on the Optimal Design of Rectangular PECT Probes for Evaluation of Defects in Conductive Structures","volume":"42","author":"Zhou","year":"2013","journal-title":"Int. J. Appl. Electromagn. Mech."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1016\/j.sna.2015.12.026","article-title":"Gradient-field Pulsed Eddy Current Probes for Imaging of Hidden Corrosion in Conductive Structures","volume":"238","author":"Li","year":"2016","journal-title":"Sens. Actuators A Phys."},{"doi-asserted-by":"crossref","unstructured":"Li, Y., Jing, H.Q., Abidin, I., and Yan, B. (2017). A Gradient-Field Pulsed Eddy Current Probe for Evaluation of Hidden Material Degradation in Conductive Structures Based on Lift-Off Invariance. Sensors, 17.","key":"ref_9","DOI":"10.3390\/s17050943"},{"key":"ref_10","first-page":"271","article-title":"The Use of Ac-Field Measurements for Crack Detection and Sizing in Air and Underwater","volume":"320","author":"Dover","year":"1986","journal-title":"Philos. Trans. R. Soc. A Math. Phys. Eng. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1016\/S0308-0161(02)00088-1","article-title":"Sizing of Cracks Using the Alternating Current Field Measurement Technique","volume":"79","author":"LeTessier","year":"2002","journal-title":"Int. J. Press. Vessel. Pip."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1016\/j.ndteint.2003.03.001","article-title":"Effect of Residual Stress on ACFM Crack Measurements in Drill Collar Threaded Connections","volume":"37","author":"Knight","year":"2004","journal-title":"NDT E Int."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.ndteint.2014.06.006","article-title":"A Feed-Through ACFM Probe with Sensor Array for Pipe String Cracks Inspection","volume":"67","author":"Li","year":"2014","journal-title":"NDT E Int."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1016\/j.ndteint.2016.01.003","article-title":"High Sensitivity Rotating Alternating Current Field Measurement for Arbitrary-Angle Underwater Cracks","volume":"79","author":"Li","year":"2016","journal-title":"NDT E Int."},{"doi-asserted-by":"crossref","unstructured":"Zhang, Y., and Li, Y. (2010, January 22\u201325). Magnetic-Field-Based 3D ETREE Modelling for Multi-Frequency Eddy Current Inspection. Proceedings of the IFIP Advances in Information and Communication Technology, Nanchang, China.","key":"ref_15","DOI":"10.1007\/978-3-642-18369-0_25"},{"unstructured":"Theodoulidis, T., and Pichenot, G. (2007, January 19\u201321). Integration of Tilted Coil Models in a Volume Integral Method for Realistic Simulations of Eddy Current Inspections. Proceedings of the 12th International Workshop on Electromagnetic Nondestructive Evaluation, Cardiff, UK.","key":"ref_16"},{"unstructured":"Reboud, C., and Theodoulidis, T. (2011, January 10\u201312). Field Computations of Inductive Sensors with Various Shapes for Semi-Analytical ECT Simulation. Proceedings of the 16th International Workshop on Electromagnetic Nondestructive Evaluation, Chennai, India.","key":"ref_17"},{"unstructured":"Theodoulidis, T., and Kriezis, E.E. (2006). Eddy Current Canonical Problems (with Applications to Nondestructive Evaluation), Tech Science Press.","key":"ref_18"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"407","DOI":"10.1016\/S0963-8695(02)00008-7","article-title":"Impedance Evaluation of Rectangular Coils for Eddy Current Testing of Planar Media","volume":"35","author":"Theodoulidis","year":"2002","journal-title":"NDT E Int."},{"key":"ref_20","first-page":"141","article-title":"Response of Horizontal-Axis Eddy-Current Coils to Layered Media: A Theoretical and Experimental Study","volume":"137","author":"Bond","year":"1990","journal-title":"IEE Proc. A Sci. Meas. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.ndteint.2016.02.001","article-title":"Pulse-Modulation Eddy Current Inspection of Subsurface Corrosion in Conductive Structures","volume":"79","author":"Li","year":"2016","journal-title":"NDT E Int."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/j.ndteint.2017.02.009","article-title":"Pulse-Modulation Eddy Current Probes for Imaging of External Corrosion in Nonmagnetic Pipes","volume":"88","author":"Li","year":"2017","journal-title":"NDT E Int."},{"unstructured":"Udpa, S.S. (2014). Nondestructive Testing Handbook Volume 5: Electromagnetic Testing, American Society for Nondestructive Testing. [3rd ed.].","key":"ref_23"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1007\/s00723-012-0427-5","article-title":"Analysis of Uniformity of Magnetic Field Generated by the Two-Pair Coil System","volume":"44","author":"Czechowski","year":"2013","journal-title":"Appl. Magn. Reson."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1161","DOI":"10.1016\/j.mspro.2014.06.189","article-title":"Characterizing Ductile Damage and Failure: Application of the Direct Current Potential Drop Method to Uncracked Tensile Specimens","volume":"3","author":"Brinnel","year":"2014","journal-title":"Procedia Mater. Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.tsf.2012.10.089","article-title":"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","volume":"525","author":"Ali","year":"2012","journal-title":"Thin Solid Films"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/8\/1747\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:44:39Z","timestamp":1760208279000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/8\/1747"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,7,31]]},"references-count":26,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2017,8]]}},"alternative-id":["s17081747"],"URL":"https:\/\/doi.org\/10.3390\/s17081747","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2017,7,31]]}}}