Applied analytical tools for the characterization of cermets

Based on the available literature, the state of the art of different analytical approaches for the characterization of cermets is discussed according to their information content as well as their applicability for routine analysis. Different wet chemical procedures for the dissolution of the binder phase were investigated and SEM and EDX were used to characterize the surface of the remaining carbides. The composition of the dissolved binder phase was determined by AAS and ICP-AES. TEM studies, owing to the superior lateral resolution of this technique, were used for the investigation of core-shell structures and other structural details of the cermet. The usual TEM procedures for imaging, i.e. bright and dark field imaging as well as electron diffraction imaging, were applied. Qualitative analyses of the phases were performed by EDX keeping in mind that TEM results might not always be representative for the whole cermet due to the small analytical volume analyzed by this technique but on the other hand yielding compositional information in the nanometer domain which cannot be easily obtained by other methods. This disadvantage of TEM for the analytical characterization of greater domains of the cermet could be overcome by the application of a recently developed 3D-SIMS system which alloys the investigation of the distribution of the main components between the binder phase and the carbide grains. In this case the limited lateral resolution of SIMS (0.5 μm) was partly improved by the high depth resolution (approximately 10 nm).