Since geothermal wells are a feasible energy source to replace fossil fuel supply many technologies have been developed to take advantage of geothermal energy. Nevertheless service conditions in geothermal facilities are due to the chemical composition of hydrothermal fluids and temperatures in many cases extreme in terms of corrosion. Therefore materials selection based on preliminary material qualification is essential to guarantee a secure and reliable operation of the facilities.This contribution deals with the evaluation of the corrosion behavior of different high-alloyed metals and ?-Al2O3 in artificial geothermal fluids simulating the conditions in the Northern German Basin a location with geothermal potential in Germany.The limitations of suitability of duplex steel F51 super duplex stainless steel F55 alloy 31 in this geothermal fluid obtained by electrochemical measurements and exposure tests are addressed. As an alternative to the suitable expensive alloy 59 showing an excellent corrosion resistance against pitting corrosion ceramic made of ?-Al2O3 represents a possibility for some parts to be used in the construction of geothermal facilities.Keywords: localized corrosion steel Ni-alloy ceramic geothermal energy