Dear Sriram Krishnamoorthy ,

The application of a protective coating of Zn is imposed on metals subjected to corrosion in aggressive environments or increase the durability of a metal over time. This coating is often obtained by hot-dip galvanizing or galvanizing on non-alloy or low-alloy steels. In recent years, powder hot-dip galvanizing with nanoparticles has also been applied. These coatings show good corrosion resistance. The application of a protective coating of Zn is uneconomically justified and expedient on corrosion-resistant steels. It is justified only when there is no other solution to the durability of the product or application in specific chemically aggressive environments.

Is Zn can be plated over SS via electrodeposition?

Dear Dr. Sriram Krishnamoorthy ,

Zinc (Zn) and zinc–nickel (Zn–Ni) electrodeposition has been widely used in many industries, such as automotive and aerospace, for corrosion protection of steel components owing to their excellent corrosion resistance.

Plating onto stainless choice is an excellent choice for various applications. You can electroplate stainless steel products using the same techniques we use for electroplating any other parts. You can electroplate carbon steel and alloy steel as well. Before plating stainless steel, you should prime it with a nickel strike to enable the plating to adhere to the steel. Then, you can deposit the metal finish using standard electroplating methods.

For more details, please see the following sources:

-Progress in Electrodeposition of Zinc and Zinc NickelAlloys Using Ionic Liquids (Review Paper)

Kranthi Kumar Maniam and Shiladitya Paul

Appl. Sci.,10, 5321 (2020)

Available at: https://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjRg6_H16jvAhXVs6QKHXB4B-kQFjALegQIIRAD&url=https%3A%2F%2Fwww.mdpi.com%2F2076-3417%2F10%2F15%2F5321%2Fpdf&usg=AOvVaw2WQdIRFFF2m0UjZO5uGpcf

and

-SPC_Surface Treatment Expert – Tech Note

Available at: https://www.sharrettsplating.com/base-materials/stainless-steel

My best regards, Pierluigi Traverso.

The question here is if you get any enhanced protection of stainless steel by using a zinc coating. In most environments, the corroson resistance of SS is higher than that of Zn.

Why at all necessary to put zinc coating on stainless steel, the latter already corrosion resistant.

The use of aqueous electrolytic plasma deposition of any conductive metal, including zinc can be deposited directly to stainless steel without the need for a nickel strike or other tie coating strike for adhesion. The use of cathodic atmospheric plasma unlike conventional electroplating creates a mixing of the substrate metal and the deposited metal providing a superior adhesion.

J.C.S. Fernandes and K. Elaya Perumal , the zinc coating is more anodic than stainless steel in most environments. Zn and stainless steel form a galvanic couple, with oxydation in Zn, and reduction in stainless steel. It is similar than a cathodic protection of stainless steel, so its protection is enhanced. And since the Zn has much larger contact area with the environment than the protected stainless steel, the corrosion of Zn due to the galvanic effect is not excessive.

Antoine Mannucci, the question is if further protection of SS is needed and that mainly depends on the environment. If chlorides are present in a significant amount, Zn cathodic protection could avoid pitting. But, in atmospheric media, where Zn coatings are normally used, a good SS won't pit. Moreover, cathodic protection may affect repassivation processes on a passive material such as SS. So, again, it is not a question on the type of action of Zn on steel, is just the fact that a well chosen SS may be enough.