Characterization of Fe2B layers on ASTM A1011 steel and modeling of boron diffusion

In this work, the ASTM A1011 steel substrate has been pack-boronized in the interval of 1123-1273 K for 2-8 h. With the used powders mixture (33.5 wt.% B4C, 5.4 wt.% KBF4 and 61.1 wt.% SiC), the iron boride layers were formed on this steel. The boronized layer/matrix was characterized by a jagged morphology. X-ray diffraction technique was used in order to identify the presence of iron boride phase. Tribological studies were also undertaken to assess the interfacial adherence of boride layer to the substrate and the values of coefficient of friction (COF) for borided and unborided samples. In addition, the mean diffusion coefficient approach was employed to estimate the diffusivity of boron in Fe2B. Moreover, this diffusion model has been verified empirically by using an extra boriding condition (at 1248 K for 2 h).