Abstract
In high temperature NaOH solution, the initial repassivation processes of anodic reaction on newly created surfaces of nickel-base alloys containing 0∼30 mass% chromium were investigated by a rapid straining electrode technique. And also the corrosion films of these alloys were mainly analyzed by ion micro mass analyzer (IMMA). The results obtained are as follows:
(1) The repassivation rate of nickel base alloys increased with increasing chromium content.
(2) The corrosion film had a double layer structure, that is, nickel hydroxide or oxide in outer layer and chromium hydroxide of oxide in inner layer. The chromium concentration in the inner layer increased with increasing chromium content.
(3) The caustic corrosion resistance seems to be influenced by the repassivation rate and the inner chromium oxide layer, and be important of the existence of the outer nickel hydroxide and/or the oxide layer.
