Modeling of the Kinetics of Boron Diffusion in Dehydrated Paste Pack-Borided AISI M2 Steel Based on Two Mathematical Approaches

Abstract

In this work, two mathematical approaches were used in order to determine the values of activation energies in the iron monoboride (FeB) and diiron boride (Fe2B) layers on AISI M2 steel. The required experimental data about the boriding kinetics of AISI M2 steel were taken from the literature to estimate the values of boron diffusion coefficients in the FeB and Fe2B layers in the range of 1,173 K to 1,273 K produced by the dehydrated paste pack-boriding. The first approach was based on the integral method, whereas the second approach employed the Dybkov model. The estimated values of activation energies for boron diffusion in the FeB and Fe2B layers were in the range of 232.77–246.86 kJ mol−1 and 218.58–231.29 kJ mol−1, respectively. Finally, the experimental thicknesses of FeB and (FeB + Fe2B) layers obtained for 1, 3, 5, and 7 h at 1,173, 1,223, and 1,273 K were compared with the predicted thicknesses by using these two approaches. A good concordance was achieved between the experimental data and the simulated results.