Comparative study of TEM sample preparation techniques for plasma-sprayed ceramic coatings

The development of advanced materials, with complex microstructures, is a p ermanent challenge to the development and application of new efficient tech niques for microstructural characterization. In ceramic coatings on metals, there exist a differential ion-milling ratio between both components, limi ting in principle the use of conventional techniques. In this work, we repo rt on a comparative study of TEM sample preparation techniques for plasma-s prayed ceramic coatings. Firstly, we have used a procedure derived from the conventional one (polishing, dimpling, ion milling), and alternatively a n ew technique using focused ion-beam milling. The material selected for this study is fine-grained alumina that was plasma-sprayed on a steel substrate . The efficiency of both techniques is discussed along with the most signif icant microstructural features of the material subject of study.