General Rule - Material for Fluid

Many pump/pipe/tube manufacturers have catalog appendices with basic information on material/fluid compatibility. This can be a good start, and is freely available. For more detail, NACE (National Association of Corrosion Engineers) is great, but I think you must be a member or purchase their literature.

Some candidate choices might include SS316L, DSS, Monel, titanium, Hastelloy, etc. It also depends on temperature and on trace chemicals that might be present, so there really is no "general rule."

Google "materials compatibility".

The Cole-Parmer corrosion resistance database will come up, among others.

If the fluid name is not known you're going to be pretty stuck. You cannot select materials based purely on pH alone. Furthermore, in some instances a material might handle a particular chemical on its' own, but when even traces of another chemical are present the result can be catastrophic.

"Generally how they are decided. Can anyone throw some light on it?"

Testing, testing, and more testing. Some people have the job of sitting in a lab testing chemicals on various materials to see what works and what doesn't.

If you don't know what the chemical is that you want compatibility with, I think you will find you cannot make a decision on a material. PH 1-14 is the entire PH scale, and is not enough information to make any kind of informed decision. You will need to know much much more.

There's only one thing that will survive this extreme environment.

That's Cargonite™ with a thin sputter coating of Unobtanium^©.

These materials can be purchased from LynDoor™ Industiies, Precarious Metals Division. WWW.LynDoor.con.

You might try www.lyndoor.com instead.

^{(I set it up as a joke)}

You're hired! You'll get a 15% commission on sales of these items.

^{Don't quit your day job, just yet.}

Based on my experience, quartzglass container coated with a thin vapor deposit of onubtanium at the thickness of some 10 microns per, is essential. You cannot get it correctly, except from thin vapor, at least today. Technology may improve in the near future to allow deposition from thick bs, but it is still uncertain.

best regards

The fluid is probably water based as pH range covers the entire aqueous band. One more information needed is temperature. If the operating temperature is not above 200ºC, PTFE as a solid or as a cladding should work.