Corundum coated sintered carbide tools

To improve their working life, hard metal tools are coated with hard materials. This can be done by CVD and PVD processes. By ordinary TiN/TiC- and diamond-layers these tools are coated in the last time also with a-Al2O3 (corundum). As well the cristallization as corundum-phase to examined with electron diffraction (SAED). With EFTEM and EDX it can be identified extrinsical phases (deposit artefacts) in the grains or grain boundaries. For these investigations it is necessary to prepare the specimens in TEM cross sections. This preparation is very expensive.