Paper on hex boron nitride, molybdenum disulfide

[jhenle]

There's been a bit of buzz lately about Cera-Tec from Liqui-Moly, purpotedly containing a form of boron nitride (hexagonal) which is supposed to coat and cover irregularities in the metal surfaces and thus reduces friction.

I have found an interesting research paper that recently tested boron nitride against MoS2 and got some interesting results.

http://www.transportation.anl.gov/pdfs/MM/857.PDF

Basically they tested in a piston/cylinder model, 6 combinations:
1. plain oil(PAO)
2. plain oil + surfactant (detergent)
3. plain oil + MoS2
4. Plain oil + surfactant + MoS2
5. plain oil + boron nitride
6. plain oil + surfactant + boron nitride

They found that even (2) oil + surfactant improves friction, and even more so (as expected) if you have MoS2 added as in 3 and 4. Moreover by spectroscopy they found a layer of particles of MoS2 deposited on the surfaces, also as expected.

However, in the case of the boron nitride they found nothing. Nada. No deposition of boron nitride on the surfaces, not even in traces. Nothing detected by spectroscopy. The coefficient of friction for the samples with BN did not change, and even the gradual reduction over time they observed in plain oil plus surfactant (2) was reversed.

Both the BN and MoS2 were nanoparticles, and the surfactant is one commonly used in oils as additive.

Given the above, how is Cera-Tec supposed to work again?

 

[Clevy]

Originally Posted By: jhenle
There's been a bit of buzz lately about Cera-Tec from Liqui-Moly, purpotedly containing a form of boron nitride (hexagonal) which is supposed to coat and cover irregularities in the metal surfaces and thus reduces friction.

I have found an interesting research paper that recently tested boron nitride against MoS2 and got some interesting results.

http://www.transportation.anl.gov/pdfs/MM/857.PDF

Basically they tested in a piston/cylinder model, 6 combinations:
1. plain oil(PAO)
2. plain oil + surfactant (detergent)
3. plain oil + MoS2
4. Plain oil + surfactant + MoS2
5. plain oil + boron nitride
6. plain oil + surfactant + boron nitride

They found that even (2) oil + surfactant improves friction, and even more so (as expected) if you have MoS2 added as in 3 and 4. Moreover by spectroscopy they found a layer of particles of MoS2 deposited on the surfaces, also as expected.

However, in the case of the boron nitride they found nothing. Nada. No deposition of boron nitride on the surfaces, not even in traces. Nothing detected by spectroscopy. The coefficient of friction for the samples with BN did not change, and even the gradual reduction over time they observed in plain oil plus surfactant (2) was reversed.

Both the BN and MoS2 were nanoparticles, and the surfactant is one commonly used in oils as additive.

Given the above, how is Cera-Tec supposed to work again?



Having used both products those findings mimic what I've also discovered. When using mos2 fuel consumption drops however when using cera-tec fuel consumtion was unchanged which tells me friction is reduced more with mos2.

Thanks for the link. I'm going to read it right now.
If a lab has used mos2 in oil and has found it reduces friction vs just the oil it kinda puts a monkey wrench in the gears of those who claim no benefit.

I'll be back.

 

[Clevy]

And cera-tec is more than just white graphite. There's ceramic nano particles which in effect should fill the surface irregularities like mos2 does and leaves a more durable surface behind.

Either way I'm sticking with mos2. It saves me a whole lot more in fuel than the 8 bucks a can costs and that's a return on the investment I can see daily in my wallet.

It's too bad they didn't test the actual liqui-moly branded stuff. Then we'd get a definitive answer one way or the other.

 

[Nate1979]

Too bad they didn't add them to fully formulated motor oil to see if there was any effect.

 

[Apollo14]

Too bad dave5358 is not around right now.

 

[Trav]

Originally Posted By: Nate1979
Too bad they didn't add them to fully formulated motor oil to see if there was any effect.

No one doubts its positive effect in engine oils from decades ago. The question is as you say, are those effects still valid in a modern engine oil?
Just wait for a page long infomercial on the Tao of MoS2 coming soon to a forum near you. LOL

 

[Garak]

Originally Posted By: Clevy
And cera-tec is more than just white graphite. There's ceramic nano particles which in effect should fill the surface irregularities like mos2 does and leaves a more durable surface behind.

Quit tempting fate. We haven't heard about graphene for a few weeks, and I don't want it to pop out of the woodwork again, as it were.

 

[Antisoshal]

Conversely: http://www.sciencedirect.com/science/article/pii/S0303264708001627

My understanding of the physics/chemistry involved in HBN is that it requires a much higher temperature and possibly pressure to deposit in the manner that provides its tribological effect. There is another military study done on ammunition testing the friction results of MOS which compared it to HBN. The study finds HBN reduces friction as measured by work done by fired round to be reduced by 12%. It seemed interesting to me that the study was done to test MOS and they used HBN for comparison.

http://www.dtic.mil/dtic/tr/fulltext/u2/a568594.pdf

I understand thats not a test with modern oil, but empirically I would say that the high heat and pressure conditions in the barrel are closer to relevant in a diesel engine than the compression-less relatively cool conditions in the test.

 

[Quest]

Originally Posted By: Apollo14
Too bad dave5358 is not around right now.


Don't you dare teasing him for he shall come back (records shown that over and over again) and spam us all over again...

or simply go along to other boards and badmouth us over there...

Q.

 

[kschachn]

This, although that was not their intent of course. But who uses pure PAO in an engine, without additives? It's not "pure oil", it's pure PAO.

And the illustrated decrease in the CoF - is that significant and does it relate to a typical motor oil?

Originally Posted By: Nate1979
Too bad they didn't add them to fully formulated motor oil to see if there was any effect.

 

[Shannow]

Similar, this paper used PAO as the carrier as well.

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3511588/Paper_on_onion-like_carbon__in

I'd give the MoS2 a little more credence, as the size of the nanoparticles at 50-70nm is at least in the range that it will interact in the spaces found in engines.

The onion carbon ones, at 5nm, would have to be stacked 4 high to fill the gap at the tightest point in a flat tappet opening event.

(Note this is not saying that either are applicable)

 

[GaleHawkins]

Originally Posted By: kschachn
This, although that was not their intent of course. But who uses pure PAO in an engine, without additives? It's not "pure oil", it's pure PAO.

And the illustrated decrease in the CoF - is that significant and does it relate to a typical motor oil?

Originally Posted By: Nate1979
Too bad they didn't add them to fully formulated motor oil to see if there was any effect.


I agree if it was something like M1, Rotella synthetic etc it would be a bit more apple to apple test.

Does a pure PAO oil have the same CoF and if so what is it?

 

[Clevy]

Originally Posted By: Garak
Originally Posted By: Clevy
And cera-tec is more than just white graphite. There's ceramic nano particles which in effect should fill the surface irregularities like mos2 does and leaves a more durable surface behind.

Quit tempting fate. We haven't heard about graphene for a few weeks, and I don't want it to pop out of the woodwork again, as it were.

Hehehe.


Gotcha