The revealing of the materials microstructure using Ar + Ion Etching by a Precision Etching and Coating System (PECS TM ) and Focus Ion Beam (FIB) techniques is described and discussed. The advantages and disadvantages of both methods in respect to materials preparation and characterisation are demonstrated on selected samples. Different kinds of materials were chosen for investigations to give a better overview on the both methods possibilities. FIB technique is very useful for the visualisation of crystallographical defects with high disorientation angle like twins, whereas PECS reveals even small crystallographical differences (subgrains, dislocation walls) induced through plastic deformation. For the optimum performance (etching and visualisation) the knowledge of the precise etching and visualisation parameters is necessary.