Mechanism of iron oxide swelling in metallization processes

Abstract

The results of stresses caused by the desorption of dissolved nitrogen atoms in point defects of allotropic phases of metallic iron obtained by solid-state reduction processes are shown. In the ferrite and austenite phases, the amounts of dissolved nitrogen and vacuums were calculated and the expansion of the surface mechanism of nitrogen adsorption was proposed, with the absorption-desorption to determine the number of its atoms and molecules adjusted to the space of the vacuums located inside the phases and to obtain the pressures and efforts generated by the confined gas. The calculated values of the efforts for the desorption of three molecules of nitrogen in a vacuum of the ferrite and austenite crystalline network were 621.2 and 727.6 Kgf/mm2, and when compared with the known values of their tensile strength (breakage) of 28 and 105 Kgf/mm2, they were 22 and 7 times higher respectively, favoring their swelling and catastrophic cracking.