Potassium Iodide compatability with s/steel or brass

[cpretty]

Hi all,

Has anyone had any experience with potassium iodide solution (5.5g/kg) and compatability with stainless steel.

I know that it is not particularly compatable with brass, but what exactly does it do?

We are not particularly worried for structural strength, but are looking at valving etc, for a fluid transfer test rig.

Thanking you for your replies in advance.

Craig

 

[TVP]

Stress corrosion cracking (SCC) and pitting are the concerns with aqueous solutions of halides, for both stainless steel and brass alloys. These ionic environments are characterized as low pH which destroys the passive film in stainless steels. The addition of increasing amounts of Mo to austenitic stainless steels (316, 317, 904L, etc.) promotes passivity and increases pitting resistance in halide environments. Copper alloys do not form a truly passive corrosion product film, and brasses (Cu-Zn alloys) are susceptible to dezincification (selective removal of Zn) and SCC in halide environments. SCC is typically an intergranular failure mechanism for both stainless steels and brass alloys.