Thermal anti-oxidation treatment of CrNi-steels as studied by EXAFS in reflection mode: the influence of monosilane additions in the gas atmosphere of a continuous annealing furnace

摘要

Surface sensitive, reflection mode EXAFS spectroscopy at the Cr and Fe K-edges was used to study the surfaces of stainless steel (EU alloy grade 1.4301 X5CrNi18-10) after different heat treatments. The thermal treatments were performed in a conveyor belt furnace at temperatures between 600 and 900 °C in different gas atmospheres containing inert carrier gases (N_2 or Ar) and different additives such as hydrogen (H_2) and monosilane (SiH_4). The ex-situ EXAFS results show that the iron and chromium in the steel can only be reduced to a metallic state, if SiH_4 was used as a reducing additive for temperatures of 900 °C. Lower temperatures and process atmospheres without silane always result in strongly oxidized steel surfaces.