ION ETCHING - STATE-OF-THE-ART AND PERSPECTIVES FOR CONTRASTING THE MICROSTRUCTURE OF CERAMIC AND METALLIC MATERIALS - PART I - DEVELOPMENTAND PHYSICS IN ION ETCHING

ion etching has proven itself particularly useful as a method of prepa ration used for the investigation of special materials. By ion bombard ement, the surfaces of materials can be etched or removed in a charact eristic way, ion beam etching of specimens in the electron microscopy is used, in particular where conventional chemical or electrochemical thinning techniques fail, such as in examination of microstructures in metallography and ceramography. In these fields however, only relativ ely few of the methods for ion etching have been standardised. The pur pose of this series of articles is therefore to demonstrate the possib iiities, advantages and disadvantages of this type of etching techniqu e for metallographical preparation. In the series of articles, the pra ctical use of the different ion etching techniques is described, toget her with the theory of ion etching and the effect that the various par ameters have on the sputtering rate. In these parts of the series, gen eral views of the historical development and theory of ion etching wil l be presented and the most important parameter, which can be measured , the sputtering yield will be explained, This is dependent both on th e properties of the ions (ion mass, ion energy, ion current density an d angle of ion incidence), as well as on the properties of the materia l being etched (crystal structure, surface finish, temperature). The v arious parameters affecting both the ions and the material itself are briefly explained.