High purity water corrosion of Stainless

[ld25]

Does molybdate or nitrate have any corosion protection of stainless in a cooling water loop? If so, is one better than the other? Does anyone know of any good links for the corrosion protection of stainless?

 

[kenvlach]

High purity water corrosion of Stainless??

High purity water doesn't (as far as I know) corrode stainless steel; the SS surface remains passive.

Sodium nitrite NaNO₂ and nitrite-molybdate solutions are used to protect common steel from corrosion due to chloride Cl^-.

If you are experiencing corrosion of SS from cooling water, I think there must be some other factors. Describe the corrosion, whether general or crevice only, water composition & pH, whether open or closed system, other metals used in the system, etc.

 

[EdStainless]

In high purity, high temperature systems there is significant corrosion of SS. Neither nitrite or molybdate will work in these systems.
There are hundreds of technical papers on the corrosion in nuclear power plants that address this issue.

= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[kenvlach]

EdStainless, this is a follow-up of earlier threads. MIC & biocides may be involved; high purity water & high temperatures are relative terms, but to my way of thinking, not involved. See

Cooling Water Treatment
thread164-135839

MIC prevention in stainless
thread338-136707

High iron content in chilled water loop
thread164-113363

Id25, please furnish the SS alloy(s), water temperature and chemistry.