Metallic materials for highly stressed oxygen nozzles and recovery boilers were studied in respect to their corrosion resistance in H-2/H2O/H2S laboratory test gas. Screening tests using ferritic and austenitic steels and nickel-base alloys were carried out and from the results promising alloys selected and tested at various temperatures. With one exception, all alloys show bell-shape temperature dependence of the oxidation kinetics. Results from studies on model alloys will be used to derive optimised alloy compositions which exhibit protective oxide scale formation in the whole temperature range considered in the present studies.