Frequently Asked Questions About Near-Frictionless Carbon Films

Description of Technology
Key Features of New Carbon Film
Projected Benefits and Industrial Participation
Is Near-Frictionless Carbon Suitable for Your Applications?

Description of Technology

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, Teflon™, 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.

Projected Benefits and Industrial Participation

Since its first observation, we have been extremely busy exploring the ultra-low friction and wear mechanism(s) of the NFC films. Accordingly, we did not know much about potential commercial uses of this coating, but a news release by Argonne in October 1997 has generated an overwhelming interest from industrial companies. Argonne's NFC film has also been featured in a number of scientific journals that are still generating interest in this new material. Argonne currently is working with three private firms to develop near-frictionless carbon coatings to increase engine efficiency, extend wear life and reduce maintenance costs for motor vehicles (more . . .). Certain components in engines operate under marginally lubricated conditions and are subject to very heavy loads causing existing materials and coatings to fail. It is hoped that a hard and slick coating on the sliding surfaces of these critical engine components will enable the realization of long-lasting and highly fuel efficient engines.

While this CRADA, along with our commitment to explore the ultra low friction and wear mechanisms of the NFC films, will keep Argonne's research team busy, Argonne anticipates that the uniqueness of this new material may lead to its use in a variety of commercial applications and Argonne is interested in finding ways to get this near-frictionless carbon film more widely studied and evaluated.

Is Near-Frictionless Carbon Suitable for Your Application?

Argonne is interested in finding partners to help develop applications for this material, but we have received a large number of inquiries, and it is impossible to adequately follow up on all of them. To help our technical staff make properly evaluate the suitability of this new material to your specific area of interest, we would appreciate your response to the following:

• Describe your application(s)
• What are your technical requirements or specifications -- temperature, environment, loads, shapes, substrates, etc.
• Economic considerations -- what's required to be competitive?
• Estimated market size -- area to be coated, number of pieces per year, etc.
• What are you using now?
• What are the primary deficiencies with your current approach? What problems do you need to solve?
• Have you looked at other carbon coatings or diamond-like coatings? Which ones? How did they work?
• Is there anything else it would be helpful for us to know?

Please send your response to Donald Knight, Office of Technology Transfer, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439. You may also fax your response to 630/252-5230 or email it to dknight@anl.gov.

For More Information

Technical Overview

Test samples of the NFC coating are available. For information on licensing, obtaining samples and collaborative arrangements, contact Argonne's Office of Technology Transfer (800-627-2596, partners@anl.gov).