Nanite News
Recent News |  Archives |  Tags |  About |  Newsletter |  Submit News |  Links |  Subscribe to NaniteNews.com RSS Feed Subscribe


More Articles
The story of animal domestication retoldThe story of animal domestication retold

Diffeomorphometry and geodesic positioning systems for human anatomyDiffeomorphometry and geodesic positioning systems for human anatomy

Thermoelectric generator on glass fabric for wearable electronic devicesThermoelectric generator on glass fabric for wearable electronic devices

Scientists grow cartilage to reconstruct noseScientists grow cartilage to reconstruct nose

Appearance of night-shining clouds has increasedAppearance of night-shining clouds has increased

Simplicity is key to co-operative robotsSimplicity is key to co-operative robots

Ancient shark fossil reveals new insights into jaw evolutionAncient shark fossil reveals new insights into jaw evolution

Gecko-like adhesives now useful for real world surfacesGecko-like adhesives now useful for real world surfaces

Deadly human pathogen Cryptococcus fully sequencedDeadly human pathogen Cryptococcus fully sequenced

Vitamin B3 might have been made in space, delivered to Earth by meteoritesVitamin B3 might have been made in space, delivered to Earth by meteorites

Chemists' work with small peptide chains may revolutionize study of enzymes and diseasesChemists' work with small peptide chains may revolutionize study of enzymes and diseases

Satellite shows high productivity from US corn beltSatellite shows high productivity from US corn belt

Sperm meets egg: Protein essential for fertilization discoveredSperm meets egg: Protein essential for fertilization discovered

The surprising consequences of banning chocolate milkThe surprising consequences of banning chocolate milk

Researchers determine how mechanical forces affect T-cell recognition and signalingResearchers determine how mechanical forces affect T-cell recognition and signaling

Running geese give insight into low oxygen toleranceRunning geese give insight into low oxygen tolerance

Galactic serial killerGalactic serial killer

Positive, negative thinkers' brains revealedPositive, negative thinkers' brains revealed

Babies prefer fairness -- but only if it benefits them -- in choosing a playmateBabies prefer fairness -- but only if it benefits them -- in choosing a playmate

A new twist makes for better steel, researchers findA new twist makes for better steel, researchers find

Renewable energy market share climbs despite 2013 dip in investmentsRenewable energy market share climbs despite 2013 dip in investments

Study finds gaming augments players' social livesStudy finds gaming augments players' social lives

A breakthrough in creating invisibility cloaks, stealth technologyA breakthrough in creating invisibility cloaks, stealth technology

Overcoming structural uncertainty in computer modelsOvercoming structural uncertainty in computer models

Monkey caloric restriction study shows big benefit; contradicts earlier studyMonkey caloric restriction study shows big benefit; contradicts earlier study

Researchers developed world's first fluorescent sensor to detect date rape drugResearchers developed world's first fluorescent sensor to detect date rape drug

Copied from nature: Detecting software errors via genetic algorithmsCopied from nature: Detecting software errors via genetic algorithms

Turning back the clock on aging muscles?Turning back the clock on aging muscles?

New study finds differences in concussion risk between football helmetsNew study finds differences in concussion risk between football helmets

Lou's clues lead to nano revelation (2/21/2010)

Tags:
nanowires, welding, gold
Two gold nanowires weld when their tips touch. -  Jun Lou/Rice University
Two gold nanowires weld when their tips touch. - Jun Lou/Rice University

Welding uses heat to join pieces of metal in everything from circuits to skyscrapers. But Rice University researchers have found a way to beat the heat on the nanoscale.

Jun Lou, an assistant professor in mechanical engineering and materials science, and his group have discovered that gold wires between three-billionths and 10-billionths of a meter wide weld themselves together quite nicely - without heat.

They report in today's online edition of the journal Nature Nanotechnology that clean gold nanowires with identical atomic structures will merge into a single wire that loses none of its electrical and mechanical properties. The process works just as well with silver nanowires, which bond with each other or with gold.

This cold-welding process has been observed on the macro scale for decades, Lou said. Clean, flat pieces of similar metals can be made to bond under high pressure and in a vacuum. But only Lou and his colleagues have seen the process happen on the nanoscale, under an electron microscope.

As so often happens in basic research, that's not what they were looking for at all. Lou and Rice graduate student Yang Lu, with collaborators at Sandia National Laboratories and Brown University, were trying to determine the tensile strength of gold nanowires by attaching one end of a wire to a probe in a transmission electron microscope (TEM) and the other to a tiny cantilever spring called an atomic force microscopy (AFM) probe.

Pulling the wire apart gave the team a measurement of its strength. What they didn't expect to see was the broken wire mending itself when its ends or sides touched. Measurements showed the reconnected wire was as strong as before.

"Before you can actually stretch something, you need to clamp it well," said Lou, who received a Young Investigators Research Program grant from the Air Force Office of Sponsored Research last year. "During the manipulation process, we observed this type of welding behavior all the time.

"Initially, we didn't pay attention to it because it didn't seem significant. But after doing a little research on the field, I realized we discovered something that may be useful."

In testing, Lou found the nanowires could be snapped and welded many times. Mended wires never broke again at the same spot; this attests to the strength of the new bond.

The wire's electrical properties also seemed unaffected by repeated breaking and welding. "We'd break a wire and reweld it 11 times and check the electrical properties every time. All the numbers were very close," he said.

The keys to a successful weld are the nanowire's single crystalline structure and matching orientation. "There are a lot of surface atoms, very active, that participate in the diffusion at the nanoscale," Lou said. "We tried gold and silver, and they weld in the same way as long as you satisfy the crystalline-orientation requirement."

Lou sees the discovery opening new paths for researchers looking at molecular-scale electronics. He said teams at Harvard and Northwestern are working on ways to pattern arrays of nanowires, and incorporating cold welding could simplify their processes. "If you're building high-density electronic devices, these kinds of phenomena will be very useful," he said, noting that heat-induced welds on the nanoscale run the risk of damaging the materials' strength or conductivity.

Lou said the discovery has caused a stir among the few he's told. "Different people see different aspects: Electrical engineers see the application side. Theory people see some interesting physics behind this behavior. We hope this paper will encourage more fundamental study."

Note: This story has been adapted from a news release issued by the Rice University

Post Comments:

Search
New Articles
ASU leads new national research network to study impacts of nanomaterials

Researchers develop ErSb nanostructures with applications in infrared and terahertz rangesResearchers develop ErSb nanostructures with applications in infrared and terahertz ranges

Virus structure inspires novel understanding of onion-like carbon nanoparticlesVirus structure inspires novel understanding of onion-like carbon nanoparticles

The motion of the medium matters for self-assembling particles, research showsThe motion of the medium matters for self-assembling particles, research shows

Domain walls in nanowires cleverly set in motionDomain walls in nanowires cleverly set in motion

Graphene nanoribbons as electronic switches

Rebar technique strengthens case for graphene

Self-assembled superlattices create molecular machines with 'hinges' and 'gears'Self-assembled superlattices create molecular machines with 'hinges' and 'gears'

Researchers probe the next generation of 2D materials

Structural insights into the inner workings of a viral nanomachineStructural insights into the inner workings of a viral nanomachine

Making the most of carbon nanotube-liquid crystal combos

Carbon nanotubes grow in combustion flamesCarbon nanotubes grow in combustion flames

Nanosheets and nanowiresNanosheets and nanowires

Nano-paper filter removes viruses

Researchers develop technique to measure engineered nanomaterials delivered to cells



Archives
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007


Science Friends
Agricultural Science
Astronomy News
Biology News
Biomimicry Science
Cognitive Research
Chemistry News
Tissue Engineering
Cancer Research
Cybernetics Research
Electonics Research
Forensics Report
Fossil News
Genetic Archaeology
Genetics News
Geology News
Microbiology Research
Parenting News
Physics News


  Archives |  Submit News |  Advertise With Us |  Contact Us |  Links
Use of this site constitutes acceptance of our Terms of Service and Privacy Policy. All contents © 2000 - 2015 Web Doodle, LLC. All rights reserved.