Dear Kunal,

See the attachment. May be useful to you.

Regards,

Vaibhav

A passive layer is a "child" of material and surrounding electrolyte, so its difficult to tell something about its durability in general. Passive state is a dynamic process of activation and repassivation. What kind of stainless steel do you observe, how are the surface conditions, which seawater at which temperature etc etc.

Regards,

Andreas

The passive layer is usually several 10 micron thick. Its durability depends on the actual Cr-content of the steel. In seawater it is usually destroyed because of chloride pitting.

Hi Reinhard, sorry, thats not correct. Passive layers of stainless steel (chromium oxide/hydroxide) are only a few "nano´s" (nm) thick. This has been investigated by XPS from a lot of researchers up to now. Very fragile layer, but with strong self-healing abilities, when all the influencing conditions in the system are uncritical (which they are most of the time, due to correct materials choice and proper processing). Best regards, Andreas

Hi Andreas,

this is true in rooom temperature electrolytes. When you oxidize Cr in high temperature steam, the layers are several µm thick. This is the reaseon for their stability in steam.

Best regards

Reinhard