Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Materials that shrink when heated

10.02.2012
New research holds promise for applications ranging from high-precision optical components to tooth fillings.
One common reason that people with fillings experience toothache is that their fillings expand at a different rate to the original tooth when, for example, drinking a hot drink. Contrary to intuition, however, not all materials expand when heated—some actually contract. Recent research on these so-called negative thermal expansion (NTE) materials has led to the discovery of alloys exhibiting unexpectedly large thermal contraction.

Controlling the thermal expansion of composites is important for producing nanometer-scale electronic circuits, as well as the next-generation fuel cells and thermoelectric devices. An ability to combine NTE materials with ‘normal’ materials which expand upon heating ensures a reduction in thermal expansion in a composite material – something that people with tooth fillings would appreciate. An example of such a composite is Invar, an iron-nickel alloy with a uniquely low coefficient of thermal expansion. As a result it is used where high dimensional stability is required, such as precision instruments, clocks or seismic creep gauges.

Koshi Takenaka at the Department of Crystalline Materials Science, Nagoya University in Japan works on NTE materials for practical applications. In the latest issue of Science and Technology of Advanced Materials (link below) he summarizes the physical mechanisms governing NTE with emphasis on recent developments.

Samples of Invar. Also known as FeNi36, it is an iron-nickel alloy notable for its lack of expansion or contraction with temperature changes. Copyright : Public Domain


Schematic of negative thermal expansion in a flexible network. Copyright : Dr. K. Takenaka, published in Sci. Technol. Adv. Mater.

Takenaka notes that, “NTE materials will expand our capability of thermal-expansion control, opening a new paradigm of materials science and technology thermal-expansion-adjustable composites”. One challenge facing the scientist is that the addition of NTE materials to composites leads to undesirable instabilities at interfaces. New methods for producing stable interfaces between the host composite and NTE compensators are of critical importance. Nevertheless, the so-called ‘one-component’ materials—such as manganese antiperovskites, zirconium vanadates, and hafnium tungstates—exhibiting negligible thermal expansion offer a promising route towards achieving this goal.

Related information

[1] ‘Negative thermal expansion materials: Technological key for control of thermal expansion’ by Koshi Takenaka, Science and Technology of Advanced Materials Vol. 13 (2012) 013001. http://iopscience.iop.org/1468-6996/13/1/013001

Affiliation: Department of Crystalline Materials Science, Nagoya University, Nagoya 464-8603, Japan
Media contacts:
Mikiko Tanifuji
National Institute for Materials Science, Tsukuba, Japan
Email: stam_office@nims.go.jp
Tel. +81-(0)29-859-2494

Mikiko Tanifuji | Research asia research news
Further information:
http://www.nims.go.jp

More articles from Materials Sciences:

nachricht Serendipity uncovers borophene's potential
23.02.2017 | Northwestern University

nachricht Switched-on DNA
20.02.2017 | Arizona State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>