Anomalous oxidation of sintered porous steels in the process of steam oxide treatment

Parts manufactured by pressing from iron-base powders possess a certain porosity. The pores form a system of communicating capillaries inside the part which absorb the ambient products (gases from the atmosphere, dissolved substances from solutions) under the action of the capillary forces and diffusion. This causes surface and internal corrosion of the material. In order to prevent oxidation of parts produced from powder materials in their transportation, storage, and operation their surface should be coated by a thin oxide film (as in blueing) in which the pores are closed by the oxides. The results of a study of the composition of oxide phases in sintered porous steels after a steam oxide treatment by two regimes are presented.[PUBLICATION ABSTRACT]