A nanometer is one billionth of a me- ter—think the size of a marble compared to the size of the Earth. Bacteria typically measures at a thousand nanometers. Li and his group manipulate particles 30 nanometers in size. Nanoparticles are being developed for use in medicine to fight cancer cells, as a catalyst to break down volatile organic compounds in the air, and in polymers for lightweight but strong sporting equipment. When successfully incorporated in metalcast- ing, nanoparticles can greatly increase the strength of lightweight alloys like magnesium and aluminum. But when Li first began work on
using nanoparticles in casting in 2003, many in the scientific commu- nity and industry didn’t think it was even possible to keep nanoparticles uniformly dispersed in molten metal that then undergoes solidification. “It was very difficult to convince oth-
ers that nanoparticles would be so ef- fective [in metalcasting] because a lot of traditional scientific study showed that it would be difficult to trap a particle that is so small,” Li said. “Most nanotechnology in metals relies on powdered metal and sintering, not solidification. They think solidification will push nanotechnology out. Well, some particles will push out, but some will stay.” With seed money from the American
Foundry Society, Schaumburg, Ill., and later the National Science Founda- tion, research work pressed on, and nanotechnology began to shift from implausible to possible to coming soon. In February, nanocomposite casting technology research was granted an estimated $10.1 million over five years from the National Institute of Standards and Technology’s Technology Innova- tion Program (TIP). The estimated $10.1 million budget includes $4,860,000 (di- rect cost) from NIST and $5.24 million matching support from team partners. TIP provides funding for high-risk, high-reward research in areas of critical national need in the U.S. The new commitment to nano- composite research in metalcasting could mean the technology will be production-ready soon, according to Dave Weiss of research partner Eck Industries, Manitowoc, Wis. “We think this is something that
could be reasonable to go into produc- tion at least in some products in three to five years,” Weiss said. “It’s definitely not pie in the sky anymore.”
28
A false color scanning electron micrograph (250,000 times magnification) shows gold nanoparticles created by NIST and the National Cancer Institute’s Nanotechnology Character- ization Laboratory for use as reference standards in biomedical research laboratories.
These cubes of cobalt (left), measuring about 50 nanometers wide, are showing scientists that on the nanoscale, a change in shape is a change in property. Unlike smaller spherical cobalt nanoparticles, nanocubes melt and fuse (right) when illuminated by a transmission electron microscope and possess different magnetic characteristics than the nanospheres.
“We think this is something that could be reasonable to go into production at least in some products in three to five years. It’s definitely not pie in the sky anymore.”—Dave Weiss, Eck Industries
Particles Pack a Punch Nanoparticles bridge bulk material
with atomic or molecular structures. While bulk material, such as alumi- num, has constant physical properties
regardless of size, at the nanoscale, size does matter. The properties of a material change as it gets incredibly small. Researchers are studying ways to achieve specific properties, such as
MODERN CASTING / March 2010
Photo courtesy of the National Institute of Standards and Technology
lhoto courtesy of Andras Vladar, National Institute of Standards and Technolog
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