Development of High Resolution Eddy Current Imaging Using an Electro-Mechanical Sensor (Postprint)
Interim rept. 25 Jun 2009-17 Jul 2011
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
Pagination or Media Count:
Typical eddy current probes are based on measuring the impedance change of a coil excited by an AC current when the coil is placed above a conductive sample. These types of probes are limited in spatial resolution to the dimensions of the coil, and coil diameter is limited by operating frequency. Because of this, the highest resolution available with these probes is on the order of 100 mum. While detecting the impedance change of the probe has limited special resolution, various methods of detecting the change in magnetic field in and around the coil have been shown to improve the resolution of a standard coil. These methods have improved the resolution in eddy current imaging to 25 nm. To date, the resolutions achievable by modern eddy current technology have failed to encompass the 100nm 100 micron range, which would be ideal for microstructure characterization of conductive materials. In this paper, a new probe, called the electro-mechanical eddy current sensor EMECS, is presented that is based on the electromechanical design to fill this resolution gap.
- Electricity and Magnetism