LAUSR

The objective of this work is to study the possibility of producing boride layers on XC38 steel by the slurry coatings technique in a muffle furnace under an ambient atmosphere. The principle of this technique consists in the application of a slurry of about 1–2 mm thickness containing boron carbide as a boron source and sodium fluoroborate (NaBF4) as a new activator on the surface of the sample to be treated and placed in a muffle furnace at 800°C for 4 hours. The obtained results show that it is possible to produce boride layers on XC38 steel by the slurry coatings technique with NaBF4 as an activator. The characterization of the obtained layers by Optical Microscopy, Scaning Electron Microscope (SEM), X-Ray Diffraction (XRD), and microhardness indicates that depending on the proportion of the boron source and the activator, these layers can be single phase (only di-iron boride [Fe2B]) at 10 % of NaBF4 or two phases iron monoboride (FeB) and Fe2B when the proportion of NaBF4 exceeds 10 %. The total thickness of the obtained boride layers is approximately 60 μm for all the slurries’ composition. But it should be pointed out that for the two-phase borided layers, the proportion of FeB boride increases with the increase of the percentage of NaBF4. The microhardness of borided layers is relatively similar for all samples and about 2,100 HV for FeB boride and 1,900 HV for Fe2B.