Electrochemical and physical characteristics of the steel treated by plasma-electrolysis boronizing

• The process was performed at the preset temperature of around 900 °C and time of 10 min.
• Corrosion resistance of sample 25% borax is higher than that of the other samples.
• Maximum hardness of samples obtained at 25 wt.% borax was 1250 HV.

Boride layers have potential industrial applications as abrasive and corrosion-resistant materials due to their high hardness values and chemical characteristics. In this study, boride layers are formed on the surface of St 14 steel samples using the plasma electrolyte method. The process was performed for a holding time of 10 min at the preset temperature of around 900 °C. The microstructure, hardness, and corrosion resistance characteristics of the boride layer are investigated by X-ray diffraction, hardness indentations and Tafel polarization. XRD results showed that boride layers are detectable on the surface of steel when the borax content of the solution is above 20 wt.%. Moreover, there are no peaks of the boride phase in X-ray patterns when the borax content is below 20 wt.%. Corrosion resistance characterization showed that layer created in 25% borax provides the best corrosion resistance. Maximum hardness values of samples processed with 10, 15, 20 and 25 wt.% borax were 750, 915, 1100 and 1250 HV, respectively.