PTFE compatibility with MIL-L-23699G Grade HTS Oils

[efulm4444]

Does any know if PTFE is compatibility with MIL-L-23699G Grade HTS Oils> if so, do you know of any resources that prove this?

 

[3DDave]

One problem might be that 23699 is not a material specification; it is a performance specification and every supplier that qualifies to that will have different additives. You need to look at the QPL for that specification and contact the individual suppliers. I've done this with other lubricants and their engineers have been very helpful. It breaks up the monotony.

 

[WKTaylor]

Here is a close approximation... Several materials listed VS hundreds of chemicals...

PTFE is listed... and so is 'Oils: Turbine'... what is NOT provided are compatibility VS temperature above or below Room Temperature*. *Conditions are based on ambient or room temperature unless otherwise noted, about 64°F (18°C) to 73°F (23°C).

May be able to get greater definition from this company. PTFE is pretty inert and capable of wide temperature extremes. CAUTION1, at even modestly elevated temperatures most plastics become increasingly soft/ductile and may distort under load. Likewise... most plastics become increasingly stiff/brittle below freezing. Exception to most of these 'rules' are incredibly expensive/exotic plastics.

NO ENDORSEMENT INTENDED... solely for ref only.
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1678809943/tips/Chemical-compatibility-chart_ISM_tdkiaf.pdf[/url]

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Also, I just thought about this... a MUCH more definitive document, especially RE turbine oils, is...
SAE AIR5693 Compatibility of PTFE Hose Assemblies With Typical Fluids Found in Aerospace Applications

Regards, Wil Taylor
o Trust - But Verify!
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation, Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", HBA forum]
o Only fools and charlatans know everything and understand everything." -Anton Chekhov

 

[3DDave]

I forgot a factor - almost never is PTFE used by itself. It is abysmally soft and cold flows easily. So you need to find out what fillers have been added to the particular sort of PTFE as well.

My buddies thought it would be a great material as an anti-friction pad for a large load. Got smeared like cream cheese. Ended up with aluminum bronze instead.

 

[WKTaylor]

BTW... this forum is for metals and metallurgy... not plastics.

Polymer Engineering (or) Plastics Engineering - general discussion forums are 'better places' for this question.

Regards, Wil Taylor
o Trust - But Verify!
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation, Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", HBA forum]
o Only fools and charlatans know everything and understand everything." -Anton Chekhov