Preparation and characterization of a new glass system inhibitor for mild steel corrosion in hydrochloric solution

Phosphate glasses, having composition 50BaO–xV2O5–(50-x)P2O5, (0 ⩽ x ⩽ 40 mol%), were prepared and characterized. The substitution of the P2O5 by V2O5 up to 10 mol%, in the binary 50BaO–50P2O5 glass entrained an increasing on Tg; beyond this value a reverse trend was observed. However, spectroscopic investigations revealed a phosphate glass system depolymerisation by systematic conversion of metaphosphate chains PO3− into pyrophosphate P2O74− and into orthophosphate PO43−. Indeed, Above 10 mol% V2O5 content, the system was highly depolymerized due to the formation of isolated PO43− structural units, resulting in poor cross-linking, making the glass system less rigid.The mild steel corrosion inhibition in 1 M HCl by phosphate glass was investigated using electrochemical measurements. The results showed that these glasses act as a corrosion inhibitor in acidic medium and their inhibition efficiencies depend to the V2O5 content in the system. In addition, it is observed that the metaphosphate chains provided a better protection than pyrophosphate P2O74− and orthophosphate PO43−.

► Phosphate glasses were prepared and characterized using FTIR and Tg.
► Results showed that Tg depends of the substitution of the P2O5 by V2O5.
► The effect of glasses on mild steel corrosion in 1 M HCl was investigated using polarization curves and EIS.
► Results showed that these glasses present a good inhibition.
► The inhibition of glasses depends to the V2O5 content in the system.