wetting agent for electropoloshing stainless steel

[Pkaushal]

hi,

Just planning to start EP of stainless steel items in 202 Gr. Somebody suggested to go for Wetting agent NON INONIC SURFACTANTS like(ALKYL polysorbate 20, polyglucoside, methylisothiazolinone,Sodium DODECYLPOLY(oxyethylene)sulfate).Rally confused. Can anybody help with this. Which one will the best and in how much volume to use.

Our requirement if MATT finish and not glossy. Going in with standard phosphoric +sulphuric acid combination. Any other chemical to be added to this solution. If not post rinse with diluted nitric + Hf will be fine or not?

 

[EdStainless]

We never used a surfactant in our EP acid.
These solutions wet very well on their own.

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P.E. Metallurgy, Plymouth Tube

 

[Pkaushal]

hi ed,

thanks for your response. Just posting text mail received from a gentlemen whom I am in touch


"The wetting agent is used in the electropolishing solution. It assists in reducing acidic vapors in the immediate area of the processing tank and reduces the “streaking” effect of gassing on parts being electropolished. It also aids in rinsing after the electropolishing process is complete. You must use a wetting agent that will withstand the extreme conditions in the acid solution"

regards
.

 

[Compositepro]

You should not need a wetting agent. The purpose of acid is to remove (etch) material from the metal surface. The purpose of a surfactant is attach to the metal surface. This is counterproductive. You do need a clean surface that the acid can work upon. The dirt that can interfere with etching is often oil or fatty acids from fingerprints and other sources. This is best removed by a caustic wash (lye, sodium hydroxide) or detergents.

 

[EdStainless]

We controlled gas spot formation with flow, lots of flow.

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P.E. Metallurgy, Plymouth Tube