Corrosion Behavior and Microstructure of Borided Tool Steel

In the present study, the corrosion behaviors of borides formed on cold work tool steel have been investigated in a 4% M HCl acid solution. Boriding was performed in a solid medium consisting of Ekabor-II powders at 850 and 950°C for 6 h. The boride layer was characterized by SEM, EDS, XRD and the hardness tester. XRD analysis of boride layers on the surface of the samples revealed the existence of FeB, Fe2B, CrB, Cr2B and MoB compounds. Depending on the chemical composition of substrates and boriding time, the boride layer thickness on the surface of the steel ranged from 13.14 μm and 120.82 μm. The hardness of the boride compounds formed on the surface of the samples ranged from 1806 to 2342 HV0,05, whereas Vickers hardness values of the untreated the samples was 428 HV0,05. The corrosion resistance of the borided steels was higher compared with that of the unborided steels. The borided steels increased the corrosion resistances of the steels 8-17- fold