A study on the diffusion kinetics of borides on boronized Cr-based steels

In the present study, kinetics of borides formed on AISI H13 hot work tool and AISI 304 stainless steels have been investigated. Boronizing treatment was carried out in slurry salt bath consisting of borax, boric acid and ferrosilicon at temperature range of 1073–1223 K for 3, 5 and 7 h. X-ray diffraction analysis of boride layers on the surface of steels revealed various peaks of FeB, Fe2B, CrB and Ni3B. Metallographic studies revealed that the boride layer has a flat and smooth morphology in the 304 steel while H13 steel was a ragged morphology. Depending on temperature and layer thickness, the activation energies of boron in 304 and H13 steels were found to be 253.35 and 244.37 kJ mol–1, respectively.