Nav: Home

Microscale superlubricity could pave way for future improved electromechanical devices

August 01, 2018

Lubricity measures the reduction in mechanical friction and wear by a lubricant. These are the main causes of component failure and energy loss in mechanical and electromechanical systems. For example, one-third of the fuel-based energy in vehicles is expended in overcoming friction. So superlubricity -- the state of ultra-low friction and wear -- holds great promise for the reduction of frictional wear in mechanical and automatic devices.

A new joint Tel Aviv University/Tsinghua University study finds that robust structural superlubricity can be achieved between dissimilar, microscale-layered materials under high external loads and ambient conditions. The researchers found that microscale interfaces between graphite and hexagonal boron nitride exhibit ultra-low friction and wear. This is an important milestone for future technological applications in space, automotive, electronics and medical industries.

The research is the product of a collaboration between Prof. Oded Hod and Prof. Michael Urbakh of TAU's School of Chemistry; and Prof. Ming Ma and Prof. Quanshui Zheng of Tsinghua University's Department of Mechanical Engineering and their colleagues. It was conducted under the auspices of the joint TAU-Tsinghua collaborative XIN Center and was published in Nature Materials on July 30. The paper can be found at https://www.nature.com/articles/s41563-018-0144-z.

Enormous implications for computer and other devices

The new interface is six orders of magnitude larger in surface area than earlier nanoscale measurements and exhibits robust superlubricity in all interfacial orientations and under ambient conditions.

"Superlubricity is a highly intriguing physical phenomenon, a state of practically zero or ultra-low friction between two contacting surfaces," says Prof. Hod. "The practical implications of achieving robust superlubricity in macroscopic dimensions are enormous. The expected energy savings and wear prevention are huge."

"This discovery may lead to a new generation of computer hard discs with a higher density of stored information and enhanced speed of information transfer, for example," adds Prof. Urbakh. "This can be also used in a new generation of ball bearing to reduce rotational friction and support radial and axial loads. Their energy losses and wear will be significantly lower than in existing devices."

The experimental part of the research was performed using atomic force microscopes at Tsinghua and the fully atomistic computer simulations were completed at TAU. The researchers also characterized the degree of crystallinity of the graphitic surfaces by conducting spectroscopy measurements.

Close collaboration

The study arose from an earlier prediction by theoretical and computational groups at TAU that robust structural superlubricity could be achieved by forming interfaces between the materials graphene and hexagonal boron nitride. "These two materials are currently in the news following the 2010 Nobel Prize in Physics, which was awarded for groundbreaking experiments with the two-dimensional material graphene. Superlubricity is one of their most promising practical applications," says Prof. Hod.

"Our study is a tight collaboration between TAU theoretical and computational groups and Tsinghua's experimental group," says Prof. Urbakh. "There is a synergic cooperation between the groups. Theory and computation feed laboratory experiments that, in turn, provide important realizations and valuable results that can be rationalized via the computational studies to refine the theory."

The research groups are continuing to collaborate in this field studying the fundamentals of superlubricity, its extensive applications and its effect in ever larger interfaces.
-end-
American Friends of Tel Aviv University supports Israel's most influential, comprehensive and sought-after center of higher learning, Tel Aviv University (TAU). TAU is recognized and celebrated internationally for creating an innovative, entrepreneurial culture on campus that generates inventions, startups and economic development in Israel. TAU is ranked ninth in the world, and first in Israel, for producing start-up founders of billion-dollar companies, an achievement that surpassed several Ivy League universities. To date, 2,500 US patents have been filed by Tel Aviv University researchers -- ranking TAU #1 in Israel, #10 outside of the US and #43 in the world.

American Friends of Tel Aviv University

Related Mechanical Engineering Articles:

A mechanical trigger for toxic tumor therapy
Cell-killing chemotherapies are designed to shrink cancerous tumors by accumulating in their ill-formed blood and lymph vessels, delivering a toxic dose to the cancer cells.
Device designed to exploit scattering of light by mechanical vibrations
Researchers at the University of Campinas's Gleb Wataghin Physics Institute (IFGW-UNICAMP) in São Paulo State, Brazil, have theoretically developed a silicon photonic device with a diameter of approximately 10 microns (μm), equivalent to one tenth of the thickness of a human hair, that would enable optical and mechanical waves vibrating at tens of gigahertz (GHz) to interact.
Nearly one-quarter of patients say mechanical heart valve disturbs sleep
Nearly one-quarter of patients with a mechanical heart valve say it disturbs their sleep, according to research presented today at EuroHeartCare 2017.
Microdevice provides novel method of measuring cell mechanical properties
Researchers from Kumamoto University in Japan have developed a new method of measuring the Young's modulus of a cell.
Achieving near-perfect optical isolation using opto-mechanical transparency
Researchers from the University of Illinois at Urbana-Champaign have demonstrated a new level of optical isolation necessary to advance on-chip optical signal processing.
A low-cost mechanical device for minimally invasive surgery
Surgeons can now use a new type of mechanical instrument to perform complex, minimally invasive procedures, also known as laparoscopic surgery, thanks to researchers and small business entrepreneurs funded by the National Science Foundation (NSF).
New mechanical metamaterials can block symmetry of motion, findings suggest
Engineers and scientists at The University of Texas at Austin and the AMOLF institute in the Netherlands have invented the first mechanical metamaterials that easily transfer motion effortlessly in one direction while blocking it in the other.
Improving the mechanical properties of polymer gels through molecular design
Research conducted at Nagoya University has revealed that the strength of normally brittle polymer gels can be increased using a design in which mobile cross-linking units are threaded on a polymer.
Sealing properties and its influence factors of spherical mechanical seal
The spherical mechanical seal which can automatically adjust the contact state of sealing surfaces is proposed to replace the frequently used plane mechanical seal in order to solve the problems that when a marine stern shaft is bent with shafting misalignment and stern bearing wear factors, etc., the sealing properties of a plane mechanical seal is declined with the increase of both contact pressure and temperature of sealing surface.
Where cells go: Mechanical and chemical cues collaborate to guide them
Living cells respond to biochemical signals by moving toward those at higher concentration, a process carefully mapped out by biologists over the past several decades.

Related Mechanical Engineering Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...