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Phosphating question

I am working on pitting corrosion concerning a martensitic stainless steel (C 0.65 %, Cr 13%) and at this moment we use a phosphating treatment (with no metallic ion) with no post treatment. Sometimes we have some corrosion problems (specially in summer) and nothing during winter. I want to know is phosphating (our kind or another one) is a good treatment against corrosion and how can I know if my steel is phosphating (photos with MEB don't show any difference between before and after phosphating).

Thank you for your help.

MaÔ MARQUES
- Compiegne, FRANCE

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I have one question what is MEB? Also phosphating of stainless steel? I would not expect it do anything. It may be removing some iron contamination of the surface but why not passivate? The phosphate may be acting as a cleaning pickle here rather producing a coating. I am puzzled as to why do you do this?

Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England