Cathodic Protection

[nickypaliwal]

How to identify whether the fluid properties are okay to allow sacrificial anode ??

eg. Electrical Conductivity etc....

 

[OGMetEngr]

What is the fluid? Material to be protected? Sacrificial material?

Suitability will depend on the electrochemical potential of both the cathode (to be protected) as well as the anode in the environment of interest, as well as the polarization characteristics, geometry, and more. Environmental variables that will determine the potential of the materials include fluid pH, temperature, conductivity, and ions present in the fluid. I'm sure there is more, someone chime in if you can think of something I left out.

 

[nickypaliwal]

Fluid is water with say 12000 PPM Chlorides and small amount of sulfates, carbonates etc.

Room Temperature and conductivity is not known. Can we assume the resistivity to be 3 times of that of sea water as it has 100 Ohms.Cm and chlorides of about 35000 PPM.

 

[OGMetEngr]

If you're trying to protect steel, stainless, and similar with a passive CP system then an AlZnIn anode may be suitable. This will polarize the material down to around -1.1 V, you'll just want to speak with an anode manufacturer to be sure you won't have any passive layers that may set up on your anode in your environment, thus making the sacrificial anode inactive. If it's not known you could also do some testing in a fluid matching your environment. Should be a pretty basic setup for a lab that knows what they are doing.

Without any more information that's the best advice I can give.

 

[OGMetEngr]

I forgot to mention, this is assuming a close to neutral pH for your fluid. A different pH will be a different story.

 

[nickypaliwal]

Thanks for the advice... I believe Sacrificial Anode can be used as a supplementary protection from your comments..However I would need to check the same with electrode manufacturer..

 

[nickypaliwal]

Sorry... ANode Manufacturer not electrode..