The End of Lubricants and the Last Tube of Grease? Not So Fast!

[M.D. Holloway]

Interesting new technology coming out. Some say in several years it will change the way bearings, gears and even engines are built and how they are lubricated:

A new, ultra-hard carbon film that we call near-frictionless carbon (NFC) provides friction coefficients of 0.001 or less when tested in a clean environment; i.e., dry nitrogen or argon. Other known or inherently low friction materials -- such as MoS2, TeflonTM, smooth diamond and diamond-like carbon films, or natural diamond -- provide friction values of 0.02 to 0.15 under the same test conditions. A steel surface well lubricated by a 10W30 motor oil gives a friction coefficient of 0.12, while an unlubricated surface has a friction coefficient of about 0.8. The friction coefficients of new carbon films in air are in the range of 0.02 to 0.06 which still are very good for dry sliding.

Another interesting feature of new carbon film is that it provides extremely low wear rates (i.e., 10-10 - 5x10-11 mm3/N.m; 100 to 1000 times lower than those of the materials and coatings mentioned above) when sliding against steel or ceramic materials. The wear rate of a well lubricated steel surface is 10-7 mm3/N.m, while that of an unlubricated steel surface is about 10-5 mm3/N.m. It looks that the friction coefficient of Argonne's NFC film is perhaps the lowest reported to date for a solid material and its wear resistance is the highest. In terms of durability, the film has an extremely long endurance life. In a recent test, we accumulated over 14 million sliding cycles without wearing through. This film was about 1 micrometer thick and deposited on a H23 steel and was tested under dry sliding conditions and in a clean test environment. Combination of these qualities makes this carbon film unique and potentially useful for a wide range of applications. The film can be deposited at room temperature on any kind of substrate (i.e., metals, ceramics, and polymers) and at fairly high deposition rates.

Key Features of New Carbon Film:
Because of its extremely low friction coefficient and wear rate, the new NFC film offers a way to make rolling, sliding or rotating machine parts more efficient and long-lasting. As mentioned above, the NFC films reduced friction by factors of 20 to 100 below the levels feasible with existing low-friction materials, coatings, or lubricants. In aerospace and transportation systems, such reduction in friction translates directly into higher efficiency and better/quieter performance, while less wear results in longer lifetime and lower maintenance cost. Therefore, the key advantages expected from these carbon films in moving mechanical assemblies are extended wear life, reduced maintenance costs, improved reliability, reduced environmental emissions, and most importantly increased energy efficiency resulting from decreased frictional losses.

[TerryBPP]

friction coefficients of 0.001 or less

Thats amazing!

[RickM]

I thought you were going to talk about "Air Bearing" technology. A shaft spins in a cushion of air. Self-cooling and no need for lube. I believe it's being developed for jet turbines and is pretty close to mass production. Interesting stuff.

[M.D. Holloway]

RickM - your right, but the airbearing concept and technology has actually been around for sometime. It is a great application but it is somewhat limited. What Argonne is doing is actually very applicable to a whole host of applications including automotive. The exciting thing is that if the technology is really stout, it can be made usefull for retro-items as well as freashly manufactured ones.

Another way to extend out machine life and increase overall reliability to another level.

[arcsine]

Sounds neat. Wonder how NFC functions under point load (transmission gears) or high-temp (combustion chambers)?

[M.D. Holloway]

Under temp I bet real well provided it has a little elongation to accomodate the metal expansion. Point load would be real interesting - bearings (roller and ball) will provide more PSI than gears I think. I bet Timkin and SKF are looking real hard at this work. I can see this being very helpfull in pump and injector valve applications as well.

The sad thing is, they will end up trying to peddle the technology off to the highest taker and no one will benefit - like what has happened with liquid metal technology.

[Neilk]

How long before it appears in F1?

That's really interesting. What's Liquid Metal?

[M.D. Holloway]

The atomic structure is the most striking characteristic of the liquid metal alloys as it fundamentally differentiates liquid metal alloys from ordinary metals.

The atomic structure of ordinary or conventional metals and alloys is periodic, where the layout of atomic elements shows repeating patterns over an extended range. This atomic structure is called "crystalline" and limits the overall performance of conventional metals.

Liquid metal alloys possess an "amorphous" atomic structure, which is truly unique. By contrast to the crystalline structure, no discernable patterns exist in the atomic structure of the unique liquid metal alloys. As such, properties superior to the limits of conventional metals can be achieved.

This amorphous atomic structure leads to a unique set of characteristic properties for the family of liquid metal alloys.

These characteristic properties are:
- High Yield Strength
- High Hardness
- Superior Strength/Weight Ratio
- Superior Elastic Limit
- High Corrosion Resistance
- High Wear-Resistance
- Unique Acoustical Properties
One of the direct results of the unique atomic structure of liquid metal alloys is very high yield strength, which approaches the theoretical limit and far exceeds the strength currently available in crystalline metals and alloys. For example, yield strength of over 250 ksi has been achieved in Zr-base and Ti-base Liquidmetal alloys (VIT-001 series). This is more than twice the strength of conventional titanium alloys.

[sewell94]

Whats the possibility of sending u some stuff to coat for a 930 engine, J/k
, But that stuff would make great coatings for engines, i wonder how much efficient the would be if the all of the friction surfaces were coated

[cstreit]

Very cool stuff!

Sooo... we're gonna need a brake to shut down our engines in 20 years.