Uniform corrosion of titanium in alkaline hydrogen peroxide conditions: Influence of transition metals and inhibitors calcium and silicate

Uniform corrosion of titanium was studied in alkaline hydrogen peroxide environments simulating pulp bleaching conditions. Corrosion rates of unalloyed Grade 2 and alloyed Grade 5 were determined as a function of hydrogen peroxide anion (HOO^-) concentration. Influences of calcium and silicate inhibitors and iron and manganese were investigated. Without inhibition titanium corroded at HOO^- content of 200 mg/l: Grade 2 0.4 mm/y and Grade 5 1.4 mm/y. Addition of calcium (Ca²⁺) and silicate (SiO ₃^2-) diminished the corrosion of Grade 2 to critical anion level 400 mg/l, but could not protect Grade 5 even at the HOO^- concentration of 300 mg/l. Presence of iron and manganese raised the critical levels of the both grades. High HOO^- anion level was observed as a notable potential difference between titanium and platinum.