June_AMP_Digital

ADVANCED MATERIALS & PROCESSES •

JUNE 2014

graphic devices. Devitrite can be produced on a large scale, simply by treating ordi-

nary window glass with heat. The crystals grow into the glass itself, making the dif-

fusers robust and resistant to damage. In addition, the high melting point of the glass

means the diffusers can withstand temperatures in excess of 500°C.

www.cam.ac.uk

Graphene keeps copper wires cool

As computer chip components

shrink, the copper wiring that connects

themmust also shrink. However, as these

wires get thinner, they heat up tremen-

dously. A potential solution to this inter-

connect fever has been found in the form

of graphene. Alexander Balandin of the

University of California Riverside, and

Kostya Novoselov, a physicist at Univer-

sity of Manchester, UK, left graphene on

the copper to see how it affected the

metal’s thermal properties. They found

that a sandwich made of graphene on

both sides of a sheet of copper improves

its ability to dissipate heat by 25%. Ba-

landin notes that the graphene itself does

not seem to conduct the heat away.

Rather, it alters the structure of the cop-

per, improving the metal’s conductive

properties. Heat moving through copper

is usually slowed by the crystalline struc-

ture of the metal. Graphene changes this

structure, causing those walls to move far-

ther apart, and allowing heat to flowmore

readily, says Balandin.

For more informa-

tion: Alexander Balandin, 951.827.2351,

balandin@ee.ucr.edu

engr.ucr.edu

Karlsruhe Institute of Technology,

Ger-

many, researchers developed microstruc-

tured lightweight construction materials of

the highest stability. Although their density is

below that of water, stability relative to

weight exceeds that of massive materials,

such as high-performance steel or alu-

minum. The new materials are inspired by

the framework structure of bones and the

shell structure of bees’ honeycombs. To pro-

duce them, 3D laser lithography was ap-

plied. Laser beams harden the desired

microstructure in a photoresist. This struc-

ture is then coated with a ceramic material

by gas deposition. Finished structures were

subjected to compression via a die

to test stability.

kit.edu/English.

Highly stable ceramic-polymer

composite framework with

individual elements only a few

hundred nm thick. Courtesy of

J. Bauer/KIT.

Fans of devitrite crystals.

Courtesy of Haider Butt.