THE INTERDEPENDENCY OF MICROSTRUCTURE, STRESS AND WEAR FOR ION-BEAM MODIFIED TOOL STEELS

The possibility of controlling independently the most important process parameters and the low processing temperature are the main advantages of ion-beam-assisted deposition (IBAD) in comparison with plasma-assisted processes. In this study information on the microstructure of film-interface-substrate systems was obtained by conversion electron Mossbauer spectroscopy (CEMS), and on the film stress by the bending substrate method. An attempt was made to connect the results with the results of application-oriented wear tests. As test systems, boron and chromium films on tools made of tool steel were chosen. It could be shown that excellent adhesion and moderate compressive stress form the best compromise for wear reduction. In the second half of the paper problems connected with IBAD of curved surfaces are treated. It is demonstrated that a non-uniform ion intensity or variations of the impact angle over the specimen surface may cause inhomogeneities of film thickness, stress and structure (texture).