Creation of a highly efficient technique to develop low-friction materials

Aug 25, 2014
Credit: Tribol Lett 55(2014)

A research group led by Dr. Masahiro Goto, a MANA Scientist at the Nano-Electronic Materials Unit, International Center for Materials Nanoarchitectonics, NIMS, and Dr. Michiko Sasaki, a NIMS Postdoctoral Researcher, and Dr. Masahiro Tosa, a Group Leader at the High Temperature Materials Unit, NIMS, created an unprecedented highly efficient method for developing friction materials with a desired frictional property. The result of this research has been published in Tribology Letters.

A research group led by Dr. Masahiro Goto, a MANA Scientist at the Nano-Electronic Materials Unit (Unit Director: Toyohiro Chikyow),International Center for Materials Nanoarchitectonics, NationalInstitute for Materials Science (NIMS; President: Sukekatsu Ushioda), and Dr. Michiko Sasaki, a NIMS Postdoctoral Researcher, and Dr. Masahiro Tosa, a Group Leader at the High Temperature Materials Unit (Unit Director: Seiji Kuroda), NIMS, created an unprecedented highly efficient method for developing friction with a desired frictional property. The method is able to drastically accelerate the development of materials that have a friction coefficient suited to the purpose of use, such as low-friction materials for reducing energy loss and high-friction materials required for high-performance brakes.

Technology for freely controlling the friction coefficient of a material is a vital factor in the development of new materials. For instance, amid the worsening of the global environment and energy issues, reduction of frictions in generators and motors directly leads to energy conservation. Under such circumstances, technology to control friction force by coating an existing structural material is drawing attention. However, since the frictional property of a coating changes considerably due to differences in the crystal preferred orientation, an enormous number of experiments with variedcompositions and crystalline structures and orientations are required in order to obtain a material with a desired frictional property, which has lengthened the development process. This time, the research group applied combinatorial technology to the development of friction materials conducted through control of crystal preferred orientation for the first time, and created a completely new technique that enables highly efficient materials development that only requires one trial experiment, eliminating the need to conduct experiments many times.

For example, zinc oxide (ZnO), which is a general metal oxide, exhibits a low-friction phenomenon when its crystal preferred orientation is optimized. However, to find the optimum crystal preferred orientation and structure for achieving such low-frictional property, it was conventionally necessary to create a large number of samples with varied crystal preferred orientations by changing the coating conditions and evaluate their crystal preferred orientation and frictional property, which required a long R&D period.

In this research, the group led by Dr. Goto analyzed the crystal structure of each microscopic region of the slide mark remaining after sliding a material while changing the conditions of the coating film (load, type of indenter material, number of sliding cycles, etc.), and discovered that it is possible to change the crystal preferred orientation by changing such conditions. In addition, the group made it possible to clarify the correlation between the friction coefficient and the crystal preferred orientation through only one experiment by also measuring the friction coefficient of the location corresponding to the crystal preferred orientation. This technique also enables control of the crystal preferred orientation of a material by a friction process alone by changing the sliding conditions, which is an achievement that significantly expands the potential of friction materials development.

The combinatorial tribological technique proposed by the group, which is able to acquire information on the crystal structure and the crystal preferred orientation required for achieving the desired friction coefficient in a short time, and can change the crystal preferred orientation of the surface layer of a material to a specific orientation by mere friction, is expected to become a leading technique in future materials research.

Explore further: Technique to develop low-friction materials with application for energy issues

More information: Masahiro Goto, Michiko Sasaki, Akira Kasahara and Masahiro Tosa, Frictional Property Depended on Crystal Preferred Orientation Analyzed by a Combinatorial Technique, Tribology Letters, Vol.55 (2014) 289-293, DOI: 10.1007/s11249-014-0349-5

Related Stories

Finnish researchers find explanation for sliding friction

May 29, 2012

Friction is a key phenomenon in applied physics, whose origin has been studied for centuries. Until now, it has been understood that mechanical wear-resistance and fluid lubrication affect friction, but the fundamental origin ...

Liquid crystal as lubricant

May 21, 2014

Thanks to a new lubricant, small gears can run with virtually no friction. Made from liquid crystalline fluid, these lubricants drastically reduce friction and wear.

Recommended for you

New insights found in black hole collisions

Mar 27, 2015

New research provides revelations about the most energetic event in the universe—the merging of two spinning, orbiting black holes into a much larger black hole.

X-rays probe LHC for cause of short circuit

Mar 27, 2015

The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, ...

Swimming algae offer insights into living fluid dynamics

Mar 27, 2015

None of us would be alive if sperm cells didn't know how to swim, or if the cilia in our lungs couldn't prevent fluid buildup. But we know very little about the dynamics of so-called "living fluids," those ...

First glimpse inside a macroscopic quantum state

Mar 27, 2015

In a recent study published in Physical Review Letters, the research group led by ICREA Prof at ICFO Morgan Mitchell has detected, for the first time, entanglement among individual photon pairs in a beam ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.