New Technique for Successful Thermal Barrier Coating Specimen Preparation for Transmission Electron Microscopy

Abstract

Reliability of thermal barrier coatings (TBC) hinges on the adhesion of a thermally grown oxide scale to an insulative ceramic topcoat and an underlying metallic bondcoat. The width of the scale and its interfaces makes transmission electron microscopy (TEM) an appropriate tool for its analysis. However, specimen preparation has proven to be a challenging obstacle leading to a dearth of TEM research on TBCs. A new approach to cross-section TBC TEM specimen preparation is described. The principal advantages of this technique are reproducibility, reduced specimen damage, and time savings resulting from decreased ion milling. This technique has been successfully applied to numerous TBC specimens with various thermal histories.

TEM and EELS measurements of interface roughness in epitaxial Fe/MgO/Fe magnetic tunnel junctions

“…They were glued face to face and thinned using tripod polishing 31 and ion milling at low angle and low voltage 32 to the electron transparency. The structures of the different layers and interfaces were investigated by TEM in high-resolution mode ͑HRTEM͒ using a TEM-scanning transmission electron microscope ͑STEM͒, a Tecnai F20 fitted with an objective lens corrected for spherical aberration ͑CEOS͒.…”