Cálculo de la energía de activación de la difusión de boro en la capa de Fe2B en la borurización por empaquetamiento de los aceros SAE 1050 y DIN UC1

The layer of iron boride (Fe2B) was formed on the surface of two steels, SAE 1005 and DIN UC1; after being subjected a treatment by packaging, and it was used to study the effect of the chemical composition on the thickness of the layer, the growth kinetics and the activation energy for boron diffusion. The mass balance equation and the parabolic growth law were used at the Fe2B/substrate interface, considering that the layer begins to grow after an incubation time (t0). The microscopic analysis revealed in the iron boride its form irregular, type saw teeth, in both steels. The present phases were identified by X-Ray diffraction, corroborating the presence of a single-phase Fe2B layer. An Arrhenius-type equation was used to correlate the layer thickness with the activation energy, which for this study was determined in 132.3 and 143.9 kJ mol-1 for SAE1005 and DIN UC1 steels, respectively.