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

Parts manufactured by pressing from iron-base powders possess a certain por osity. The pores form a system of communicating capillaries inside the part which absorb the ambient products (gases from the atmosphere, dissolved su bstances from solutions) under the action of the capillary forces and diffu sion. This causes surface and internal corrosion of the material. In order to prevent oxidation of parts produced from powder materials in their trans portation, storage, and operation their surface should he 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 s teels after a steam oxide treatment by two regimes are presented.