A major aim in today's development of aircraft and land-based gas turbines is the higher efficiency of the combustion process. The base material of the components is optimized for its mechanical properties, such as its creep strength or low and high cycle fatigue behaviour. Therefore, the corrosion and oxidation resistances have to be improved by an overlay coating. In fact, most Ni-based turbine blades are protected by an MCrAIY overlay. The conventional deposition method for this coating is low pressure plasma spraying (LPPS). As a result of new demand on the quality of hot gas corrosion-resistant MCrAIY coatings, processes that are alternatives to LPPS are under investigation. Evaporation with a cathodic are is one possibility with technical and economical potential. Are PVD systems are in use for several applications. Most actual target materials are only made of one or two elements. Therefore, the study of the behaviour of the are, running on multicomponent target materials, such as the MCrAIY compositions with 5-7 elements used, is very important. The paper reports on the basic deposition phenomenas of the cathodic are and presents the coating compositions and structures in the ''as-deposited'' and homogenized states. It is shown that the chemical coating composition is different from that of the cathode material, but the difference is relatively small, so that the composition desired in the coating can be reached by proper adjustment of the cathode material. The morphology of the MCrAIY coating shows the two- or three-phase structure which is typical for this type of hot gas corrosion-resistant overlay. A sufficient bond strength of the coating was measured, so that the industrial application of this coating is possible. The process itself offers new possibilities, such as the deposition of multilayer structures and the combination of the MCrAIY with a high temperature diffusion barrier, so that new improvements of the coating system can be achieved in one step. Summarizing the evaluation of the results shows that the are technology is competitive with the conventional deposition techniques and offers some new possibilities for improved complex coating systems.
