March_AMP_Digital

15 / 62

A D V A N C E D
M A T E R I A L S
&
P R O C E S S E S |
M A R C H
2 0 1 6
1 5
NANOTECHNOLOGY
BRIEFS
Aleris, Cleveland, offers a new 7017 aluminum alloy in North America for commercial plate and defense
uses. After extensive review and testing, the U.S. Army Research Lab issued MIL-DTL-32505 for use in armor
applications. 7017 offers high strength, good weldability, and corrosion resistance. It is currently used in
Europe and Asia on combat vehicles to achieve superior ballistic protection. aleris.com.
NANORIBBON COMPOSITE
MELTS ICE
Researchers at Rice University,
Houston, developed a thin, conductive
coating that can serve as a real-time
de-icer for aircraft, transmission lines,
and other surfaces exposed to winter
weather. The coating consists of an ep-
oxy lacedwith interconnected graphene
nanoribbons that conduct electricity
across the material, heating the sur-
face and melting ice. The team spread a
thin coat of the composite—consisting
of no more than 5% nanoribbons—on
part of a helicopter rotor blade, then re-
placed the thermally conductive nickel
abrasion sleeve used as a leading edge.
When a small voltage was applied, the
coating delivered electrothermal heat,
or Joule heating, raising the compos-
ite’s temperature to more than 200°F.
This was enough to melt 1-cm-thick ice
on a static blade in a -4°F environment.
For surfaces in motion, the
thin layer of water that forms on the
surface after heating begins should
be enough to loosen and dislodge ice
before it is completely melted. “Apply-
ing this composite to wings could save
time and money at airports where the
glycol-based chemicals now used to
de-ice aircraft are also an environmen-
tal concern,” says chemist James Tour.
Additionally, the coating could help
protect aircraft from lightning strikes
and provide an extra layer of electro-
magnetic shielding. .
NEW NANOSTRUCTURE
DISCOVERED
A previously unknown, 3D nano-
structure consisting of graphene sheets
was discovered by a staff scientist at
the Institute of Physical Problems,
Russian Federation. The new nano-
structure is a multilayer system of
parallel hollow channels with a quad-
rangular cross section extending along
the surface. Though this structure is
unlike anything previously observed
in graphite, the wall thickness of less
Box-shaped graphene—a 3D nano-
structure consisting of graphene sheets.
Courtesy of Rostislav Lapshin.
BRIEF
Defense Advanced Research Projects Agency (DARPA), Arlington, Va., launched its Atoms to Product program to
develop technologies and proc sses for ass mbling na om ter-scale pi c s into sy tems, components, r materi-
als that are at least millimeter-scale in size. DARPA recently selected 10 companie t tackle this challenge: Zyv x
Labs, Richardson, Texas; SRI, Menlo Park, Calif.; Boston Univ rsity; University of N re Dame, South Bend, Ind.; HRL
Laboratories, Malibu, Calif.; PARC, Palo Alto, Calif.; Embody, Norfolk, Va.; Voxtel, Beaverton, Ore.; Harvard University,
Cambridge, Mass.; and Draper Laboratory, Cambridge, Mass. The program calls for closing the assembly gap in two
steps—from atoms to microns and frommicrons to millimeters. .
than 1 nm and the quadrangular cross
section of the channels clearly indi-
cate that the channel walls/facets are
graphene planes. It is hypothesized
that the structure was formed from a
series of mechanical deformations of
graphite, which is layered by nature.
Because the nanochannels have a
quadrangular cross section, the newly
detected structure is called box-shaped
graphene (BSG). Preliminary analysis
indicates that the nanostructure could
be used in applications such as ultra-
sensitive detectors, high-performance
catalytic cells, nanochannels of micro-
fluidic devices, high-performance heat-
sink surfaces, enhanced rechargeable
batteries, and high-capacity sorbents
for safe hydrogen storage. .
Graphene nanoribbon-infused epoxy embedded into a helicopter blade. Courtesy
of the Tour group.