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Carbon steel and stainless steel will be in contact. How do I avoid corrosion?

Q: I want to fabricate a SS316L tank, but legs and supports are to be made of carbon steel. What kind of painting shall I provide for carbon steel as it will be in contact with stainless steel and I would like to avoid any corrosion. Is the below painting specs OK?

2 coats
110 µm
Sweep blasting, which in any case shall be carried out with abrasive free of any iron or ferrous components.
One priming coat of a two-pack epoxy-based paint, with zinc phosphate corrosion inhibitor
NDFT: 60 µm
One final coat of polyurethane paint, modified so that it may be easily recovered by itself.
NDFT: 50 µm., Finish: glossy

A: There will be no risk of galvanic corrosion as long as the tank legs are connected in a manner such that the stainless steel and carbon steel are not both in contact with a common electrolyte. Painting the carbon steel legs is a good idea for preventing corrosion and an epoxy coating as you suggest has very good corrosion resistance. I would work with your coating supplier to develop specs for your specific application. As always, surface preparation is very important when applying a coating. In general for carbon steels, a surface preparation of SSPC-SP-6 (Commercial Blast) or better is recommended for epoxy coatings. Again, I would recommend working with your coating supplier to establish the surface preparation required. I removed your references to a specific coating manufacturer as it is generally our practice not to endorse a specific product.

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