#1 Damascus Steel and Carbon Nanotubes
Posted: Wed Nov 15, 2006 4:28 pm
LinkThe Telegraph wrote: Nanotube secrets of Damascus steel blade
Last Updated: 12:01am GMT 15/11/2006
For hundreds of years, some of the keenest minds searched in vain for the secret of how blacksmiths in the ancient Middle East fashioned a tough and flexible metal known as Damascus steel.
The metal was highly prized for its extraordinary mechanical properties and an exceptionally sharp edge, and may have helped Islamic armies repel European crusaders with inferior weapons.
The search for the secret of the shimmering alloy may now be nearing an end, thanks to a study that reveals that the blacksmiths unwittingly managed to create "nanotubes" of carbon, structures at levels of a billionth of a metre.
Elements introduced during the forging process gave rise to the earliest carbon nanotubes on record, according to a study in the journal Nature by a team led by Prof Peter Paufler of the Technische Universitat Dresden.
The team used electron microscopy to study a specimen from a Damascus sabre made in the 17th century. Some remnants show evidence of carbon nanotubes. These, in turn, may have helped form iron carbide nanowires, which might explain the strength and beautiful pattern of the coveted Damascus blades.
Sir Walter Scott's fictional tale of the Crusades described the Islamic army's swords as being "of a dull blue colour, marked with ten millions of meandering lines.".
"To get the pattern, they made grooves into the blade and forged it to remove the steps. This was repeated many times," said Prof Paufler.
Damascus blades are thought to have been forged from small cakes of steel known as "wootz", probably produced in India. A sophisticated treatment was then applied to the steel, but details of this were lost in the 18th century.
Prof Paufler believes that, as further details of this material emerge it might be possible to reproduce the long-lost recipe.