FIB-Tomography and 3D Reconstruction of Crater Formation due to Discharge Phenomena

摘要

The erosion process due to discharge phenomena determines the extent of material degradation in make-break contacts and other electrical devices. During sparking, plasma erosion craters are formed on the surface of the materials. In this paper, a detailed characterization of the crater formation is given on the micro and nano scale. In addition to well known contact materials, in this study, specially designed multilayer model systems have been exposed to single discharges in a well controlled test facility. The resulting formation of erosion craters was carefully analyzed in a dual beam workstation via precise FIB-target preparation and careful serial sectioning combined with SEM imaging. From the image stacks, a complete 3D reconstruction of the craters can be derived. The resolution of this so-called FIB nanotomography is well below 1 μm and may reach 1-10 nm depending on the specific slicing conditions. Using this technique, the effects of microstructure modification including melting, material transport and pore formation across and in particular below the crater was analyzed quantitatively. Based on these observations, the interaction between the discharge and the material, especially the temperature distribution, can be constraint. In addition, the volume of molten material can be determined.