On the inhibition action of fluoride and phosphate ions on the intercrystalline corrosion of austenite stainless steels in strongly oxidizing media

Regularities of separate and combined effect of fluoride and phosphate ions on intercrystallite and general (uniform) corrosion of austenite stainless steels in strong-oxidizing media are revealed. It is shown that inhibition effect achieved by introduction of the ions indicated to HNO3 + Cr6+ solution, increases sharply with an increase of chromium content in austenite stainless steels and is much less dependent on nickel concentration in them. The maximum drop of corrosion rate is caused by combined introduction of phosphate and fluoride to solution. 19 refs.; 5 figs.; 1 tab