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

Abstract Phosphate glasses, having composition 50BaO– x V 2 O 5 –(50- x )P 2 O 5 , (0 ⩽ x ⩽ 40 mol%), were prepared and characterized. The substitution of the P 2 O 5 by V 2 O 5 up to 10 mol%, in the binary 50BaO–50P 2 O 5 glass entrained an increasing on T g; beyond this value a reverse trend was observed. However, spectroscopic investigations revealed a phosphate glass system depolymerisation by systematic conversion of metaphosphate chains PO 3 − into pyrophosphate P 2 O 7 4− and into orthophosphate PO 4 3− . Indeed, Above 10 mol% V 2 O 5 content, the system was highly depolymerized due to the formation of isolated PO 4 3− 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 V 2 O 5 content in the system. In addition, it is observed that the metaphosphate chains provided a better protection than pyrophosphate P 2 O 7 4− and orthophosphate PO 4 3− .