PTFE Additives...looks like they DO get in.

[Shannow]

http://phi-gmbh.eu/wp-content/uploads/2013/10/Mapping-Motor-Oil-Additives-on-a-Cam-Shaft-Lobe.pdf

Quote:
Application Note1Mapping Motor Oil Additiveson a Cam Shaft Lobewith PHI Scanning XPS MicroprobesIntroductionThe wear resistance of internal combustion engine parts can be improved by using appropriate motor oil additives.Extreme pressure and temperature conditions exist in areas where moving parts are in contact. These conditions will cause the molecular structure of properly chosen additives to break down and result in theformation of wear resistant surface compounds (iron phosphates and sulfides are typical). The chemistryand spatial distribution of such surface compounds can be probed with x-ray photoelectron spectroscopy


Quote:
Fluorine was detected and was found to be concentrated in the wear track of the cam lobe. The F 1s binding energy indicated that the fluorine was in a metal fluoride state demonstrating a conversion from the original fluorocarbon form.


Have used them in the past (worked on a couple of oil burners), but not a big fan of halides running around in my engine.

Posted not because I'm saying that the reactions that were identified were beneficial...could simply be a form of corrosion, not AW layers.

 

[Shannow]

http://marketplace.yet2.com/app/list/techpak?id=52652&sid=20&abc=0&page=tpprint

hmmm...

 

[lubricatosaurus]

SAE Paper 982440
http://papers.sae.org/982440/
That was a 1998 Slick50 company report. Teflon was the star of the show. Where is it now?

 

[Ducked]

Interesting.

They say " The F may contribute to wear resistance while the Zn (as an oxide) is believed to be present as an inconsequential reaction product." but they map its distribution.

"Sulfur and phosphorus from the ZDDP additive were also observed in point spectra within the wear track but were absent outside the wear track", but they don't map their distribution, saying they formed less than 10% of the surface, and were not of primary interest.

From this its hard to see what criteria they are using to class one element as an anti-wear component, and others as "inconsequential", but on the face of it they seem to be deprecating the role of ZDDP.

I suppose promoting the technique is their main interest at this stage, though.

 

[Shannow]

Originally Posted By: Ducked
From this its hard to see what criteria they are using to class one element as an anti-wear component, and others as "inconsequential", but on the face of it they seem to be deprecating the role of ZDDP.

I suppose promoting the technique is their main interest at this stage, though.


My reading was that they were discounted only because they are the "normal" effect, and they were looking for the ptfe interaction.

 

[Ducked]

Originally Posted By: Shannow
Originally Posted By: Ducked
From this its hard to see what criteria they are using to class one element as an anti-wear component, and others as "inconsequential", but on the face of it they seem to be deprecating the role of ZDDP.

I suppose promoting the technique is their main interest at this stage, though.


My reading was that they were discounted only because they are the "normal" effect, and they were looking for the ptfe interaction.


I wouldn't know what the normal effect would be, certainly not with this technique, at this level of detail, but if that's their take you'd think they might have looked at the "normal" case too, (without PTFE) since it seems quite likely the two additives will interact, and have different effects alone.

More specifically, I wouldn't know if Zinc Oxide is normally "inconsequentially" present in such tribofilms. This might be common knowledge, but a bit of casual Googling didn't find it.

Google books (in Coatings Tribology: Properties, Mechanisms, Techniques and Applications in ...By Kenneth Holmberg, Allan Matthews) has "The friction coefficient of ZnO films against a steel ball was between 0.16 and 0.34. Friction was in the beginning sensitive to load and sliding speed but once a smooth wear scar was formed, it was very stable" (Prasad and Zabinski (1997) but that's a rather different experimental setup.

In an MsC literature survey..."Martin, in 1999, was the first to propose that the reaction between long chain-length polyphosphates and iron oxide, energetically favorable on the basis of the principle of hard and soft acids and bases (HSAB) [43], could also play a role
in the antiwear mechanism [44]. According to his hypothesis the long chain-length
polyphosphates could limit wear by “digesting” the abrasive iron oxide particles,
forming zinc oxide and shorter-chain-length mixed iron/zinc phosphates"

The context of the first, at least, seems to be "third body" reformation of wear debris.

 

[Pontual]

Looks like everything that works well are later put aside. Graphite, Moly, PTFE, what ever. For aparent no reason. Why?

 

[Pontual]

They make the new oil black isnt convincent to me, for the former 2.

 

[Jetronic]

I have adiesel, what does it matter the oil goes in black?

BTW, graphite or moly in oil does not look the same as soot in oil, believe it or not.

Graphited/mos2 oil is a matte black (sometimes with metallic like shimmer), soot turns oil into a shiny black

 

[Pontual]

The metalic light reflexive (shiny black) comes from the base oil, not from contaminant, I believe. As solid lubricants making the oil a non reflexive and opaque (black mate) with small metal shimmer running, it is a good insight.