An investigation into the electrochemical behavior of hydrogen peroxide on TiO₂ treated Type 304 stainless steels in high temperature water

Titanium dioxide (TiO₂) coupled with ultraviolet irradiation was selected as a coating material for corrosion mitigation of Type 304 stainless steel (SS) in high temperature with the presence of hydrogen peroxide (H₂O₂). Type 304 SS specimens were pre-oxidized in oxygenated pure water at 288degC for 14 days. The pre-oxidized specimens were deposited with TiO₂ nanoparticles by hydrothermal deposition at 150degC and 280degC for 4 days in pure water with a TiO₂ concentration of 10 ppm and 100 ppm. Electrochemical polarization analyses were conducted to investigate the corrosion behavior of both TiO₂-treated and pre-oxidized specimens in 288degC pure water with H₂O₂ concentration of 300 ppb. Ultraviolet (UV) irradiation was then imposed upon the TiO₂-treated specimens to examine if there was any photoelectric effect on the corrosion behavior of the treated specimens. The TiO₂ loading on the specimen treated at 280degC was significantly greater than that treated at 150degC, as verified by the ICP-MS loading measurements. Preliminary results showed that UV irradiation on the TiO₂ treated specimens led to decreases in corrosion rate of the specimens. Further examinations on the impact of UV irradiation on the corrosion behavior of TiO₂ treated Type 304 SS specimens in H₂O₂-rich pure water are being conducted. (author)