A study was made of how the oxidation resistance in air of Fe-Mn-Al and Fe-Mn-C alloys at high temperatures is affected by the addition of small amounts, up to 3% silicon. An alloy containing 28% manganese, 8% aluminium, 2.4% silicon and 7 % carbon showed good behaviour up to 950°C, with a weight increase of less than 1 mgcm-2 after 170 hours of testing at constant temperature. As the silicon content fell there is an appreciable reduction in the limiting temperature for acceptable resistance. The alloys without aluminium already showed considerable oxidability at 600°C. Oxide formation mechanisms were examined as a function of time and temperature, with thermogravimetric tests and ESCA and EDS analyses.
