scholarly journals SELF-CONSISTENT SWEPT FREQUENCY EDDY CURRENT MEASUREMENTS FOR CHARACTERIZATION OF NEAR SURFACE MATERIAL CONDITIONS

2009 ◽  
Author(s):  
C. C. H. Lo ◽  
A. M. Frishman ◽  
Y. Shen ◽  
N. Nakagawa ◽  
Donald O. Thompson ◽  
...  
Keyword(s):  
Eddy Current ◽  
Surface Material ◽  
Near Surface ◽  
Self Consistent ◽  
Material Conditions

Limitations of eddy current inspection for the characterization of near-surface cracks in railheads

2021 ◽  
pp. 095440972110295
Author(s):  
Rayendra Anandika ◽  
Jan Lundberg
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Crack Depth ◽  
Surface Cracks ◽  
Important Conclusion ◽  
Near Surface ◽  
Eddy Current Inspection ◽  
Signal Response ◽  
Crack Profile

Eddy current (EC) testing is the most commonly used method to inspect near-surface cracks in railheads. Monitoring surface defects periodically is important to assess the track quality for serving daily operations. Nevertheless, despite being used in many countries, this method has limitations when characterizing cracks under the rail surface. Theoretically, EC testing is unreliable for the inspection of many cracks situated too close to each other in a concentrated location. This study has aimed to prove these limitations. EC signals from inspected cracks were compared with real crack profile parameters, i.e. depth and area, which were delivered by slicing the inspected cracked spots into 0.65 mm-thick pieces. The results show that the EC signal responses to the parameters of area and depth may lead to misleading measurements of the near-surface crack depth in the railhead. For instance, a shallower crack with a larger area can generate a higher EC signal response than a deeper crack with a smaller area. Another important conclusion is that the EC testing in this experiment could not be used to measure densely located cracks, which are those near-surface cracks which are typically found in a rail track.

Comparison of Ion-Milling Techniques For Cross-Sectional TEM of Semiconductors

1985 ◽  
Vol 43 ◽  
pp. 166-167
Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook
Keyword(s):  
Analytical Techniques ◽  
Sample Surface ◽  
Ion Milling ◽  
Cross Sectional ◽  
Reliable Technique ◽  
Near Surface ◽  
Transmission Electron ◽  
Thin Region ◽  
Transient Thermal

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

Characterization of the Hydrogen Migration in a VT1-0 Titanium Alloy by Thermo-EMF and Eddy Current Nondestructive Control Methods

2020 ◽  
Vol 2020 (11) ◽  
pp. 1276-1282
Author(s):  
Syui Shupen ◽  
V. V. Larionov ◽  
V. N. Kudiyarov ◽  
R. R. Elman ◽  
A. M. Lider
Keyword(s):  
Titanium Alloy ◽  
Eddy Current ◽  
Control Methods ◽  
Nondestructive Control ◽  
Hydrogen Migration
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