FABRICATION AND CHARACTERIZATION OF PLASMA ELECTROLYTIC BOROCARBURIZED LAYERS ON Q235 LOW-CARBON STEEL AT DIFFERENT DISCHARGE VOLTAGES
Abstract
The influence of applied voltage on the plasma electrolytic borocarburizing (PEB/C) layer of Q235 low-carbon steel in high-concentration borax solution was investigated. XRD and XPS spectra of PEB/C layer confirmed that the modified boride layer mainly consisted of Fe2B phase, and the FeB phase only exists in the loose top layer. The applied voltage on Q235 steel played a key role in determining the properties of hardened layers. The thickness and microhardness of boride layers increased with the increase of the applied voltage, which led to superior corrosion and wear resistances of Q235 low-carbon steel. The diffusion coefficient (D) of boride layer at 280, 300 and 330V increased with borocarburizing temperature and ranged from 0.062×10−12m2/s to 0.462×10−12m2/s. The activation energy (Q) of boride layer growth during PEB/C treatment was only 52.83kJ⋅mol−1, which was much lower than that of the conventional boriding process.
