Engineers Uncover Factors That Control Ion Motion In Solid Electrolytes

University of Cincinnati researchers show for the first time that they can connect an increase in electrical (ionic) conductivity with flexibility of their networks. The same team of researchers discovered intermediate phases seven years ago in amorphous or disordered materials where networks are covalently bonded.

“We find that when networks become flexible their electrical conductivity increases precipitously,” says Deassy Novita. “Now we will be able to chemically tune these materials for specific applications. For example, the batteries implanted in patients who have heart pacemakers make use of a solid electrolyte.”

Novita is a third-year graduate student working in the lab of Punit Boolchand, professor of electrical engineering in the University of Cincinnati’s College of Engineering. Originally from Indonesia and now a U.S. citizen, Novita began the ground-breaking research as part of her doctoral thesis.

"This system has been studied by about 35 groups all over the world over the past two decades. We are the first to make these samples in a ‘dry’ state,” says Boolchand. “Most people who studied these materials produced them unwittingly in the laboratory ambient environment where the relative humidity is typically 50%, and that leads to samples that are — so to speak — in a ‘wet’ state. By special handling of the materials, we were able to produce them in a dry state, where we can see the intrinsic behavior of these materials.”

"The intrinsic behavior shows samples to exist in three elastic domains," Boolchand explains. "In the first domain, at low AgI (silver iodide) content (less than 9.5%) they form networks that are rigid but stressed. In the second domain, called the “intermediate phase,” at a slightly higher content of AgI (9.5 to 37.8%), they form networks that are rigid but unstressed. And finally in the third domain, at AgI content of 37.8% and higher, their networks become flexible."

The UC research team showed for the first time that such intermediate phases also exist in networks that are ionically conducting. In the flexible phase of these materials, “silver ions move like fish through water,” Boolchand says.

The next step in their research will be to understand why traces of water change the behavior of these electrolytes so drastically and to understand if the behavior observed here of three elastic domains is a general feature of all electrolyte glasses or is it peculiar to this very well studied material. “We think the behavior will be observed in general in solid electrolytes,” says Boolchand.

The current work was supported by a National Science Foundation grant. Published in “Fast-ion conduction and flexibility of glassy networks,” Physical Review Letters.

Authors: Deassy I. Novita, Punit Boolchand, Department of Electrical and Computer Engineering, University of Cincinnati, M.Malki, Centre de Recherche sur les Matériaux a Haute Température, Université d’Orléans, France, M. Micoulaut, Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie, Paris, France

http://www.sciencedaily.com/releases/2007/05/070508102827.htm

Suspended In Space: Researchers Make Important Discovery About Materials

A NASA-funded study in materials science has yielded a discovery that may significantly change the way electronics, paint, cosmetics and pharmaceutical industries develop products.

Researchers discovered a new approach for suspending fine particles in fluids. Such collections of particles, called colloids or colloidal suspensions, may help researchers better understand how to manipulate small particle assemblies found in fluids such as water or organic solvents (e.g., ethanol).

According to a paper co-authored by a NASA researcher at the University of Illinois at Urbana-Champaign, which will appear in today's issue of the Proceedings of the National Academy of Sciences, the authors have devised a process that stabilizes particles in fluids to prevent them from otherwise organizing themselves or coagulating into a disordered gel-like structure. The authors have named this approach "nanoparticle haloing."

"Paint is an example of a fluid that contains suspended colloidal particles. If such particles become unstable, they clump together causing the paint to thicken substantially. This limits the product's shelf life. By using the nanoparticle haloing approach, we can control the behavior and structure of materials in fluids," said Dr. Jennifer Lewis, co-author, NASA researcher and professor at the University of Illinois.

Lewis and her colleagues conducted the research under a grant from NASA's Office of Biological and Physical Research, Washington, DC. The research program offers investigators the opportunity to use a microgravity or low-gravity environment to enhance understanding of fundamental physical and chemical processes associated with materials science.

"NASA scientists are using microgravity to examine the properties and structures of materials and the role processing plays in creating the materials. By subtracting gravity from the equation, we are better able to see what is happening as a material is produced," said Dr. Kathie Olsen, Acting Associate Administrator for Biological and Physical Research at NASA Headquarters.

By tailoring the interactions between particles, the researchers were able to engineer the desired degree of colloidal stability into the mixture. "That means we can create designer colloidal fluids, gels and even crystals," Lewis said. "This designer capability will assist us in developing improved materials such as photonics." Photonics are materials that control the flow of light.

For example, Lewis has teamed with co-author Paul Braun, another professor of materials science and engineering at the University of Illinois, to explore the use of these nanoparticle-stabilized colloidal microsphere mixtures in assembling robust periodic templates for photonic band gap materials. The researchers recently were awarded funding by the National Science Foundation to pursue such efforts.

Lewis and her students are also studying the structure and flow behavior of colloidal fluids and gels assembled from these microsphere-nanoparticle mixtures. By simply varying composition, the researchers can produce systems whose properties vary dramatically. Such studies provide the foundation of ongoing efforts in the area of colloidal processing of electrical ceramics.

In addition to Lewis and Braun, the research team included University of Illinois doctoral students Valeria Tohver and James Smay, from Lewis' group, and graduate student Alan Braem from Carnegie Mellon University, Pittsburgh.

More information on NASA's Biological and Physical Research Program is available at: http://spaceresearch.nasa.gov

Additional information about this research is available at: http://colloids.mse.uiuc.edu

NASA's Marshall Space Flight Center, Huntsville, AL, manages the Materials Science Program for the Office of Biological and Physical Research. Marshall is also NASA's lead center for microgravity research -- conducting unique scientific studies in the near-weightlessness of space to improve life on Earth.

http://www.sciencedaily.com/releases/2001/08/010802081504.htm

UNC-CH Physicists Find Atoms Of Chilled Metallic Liquids Chiefly Move In Lockstep

CHAPEL HILL - For the first time, atomic-scale measurements have revealed that atoms in a metallic liquid cooled significantly below the melting point - also known as a super-cooled liquid -- chiefly move together in clustered lockstep.

The effect is something like that of a phalanx of ancient Greek soldiers marching into battle or commuters moving on the platform of a crowded subway.

Such information is important in part because it helps reveal and explain the behavior of liquids having a strong tendency to form bulk metallic glasses, a new class of engineering materials with highly unusual properties, scientists say. First reported in 1993, the materials have thousands of potential uses in industry, the military, sports and other areas.

"What we have done is to shed some light on the mechanisms of atomic motion in the glass transition temperature region, around 650 degrees Fahrenheit in the materials we were working with," said Dr. Yue Wu, associate professor of physics and astronomy at the University of North Carolina at Chapel Hill. "This could be significant for understanding the nature of glass transition, which occurs when liquid cools rapidly and changes from a molten form to an amorphous solid without crystallization.

"The transition is a universal phenomenon that's been observed in almost all materials and plays a key role in many areas from food preservation to the forming of glass art objects."

A report on the research appears in the Nov. 11 issue of the journal Nature. Besides Wu, authors are Drs. X.-P. Tang, assistant research professor in physics at UNC-CH, Ulrich Geyer of Gottingen University in Germany, Ralf Busch of Oregon State University and William L. Johnson of the California Institute of Technology.

The study involved examining slow beryllium atomic motion on both microscopic scales using nuclear magnetic resonance (NMR) and macroscopic scales using diffusion measurements in zirconium-based bulk metallic glasses, alloys discovered by Johnson and a student at Cal Tech.

Tang and Wu employed a new NMR technique they developed to determine how local environments of beryllium atoms change when motion occurs and the rate of such changes.

"Atoms in a chilled metallic liquid manage to move more efficiently as a group than individual hopping, although the latter survives better at lower temperatures below the region of glass transition," Wu said.

"These glass-forming metals have great promise in a variety of technical applications ranging from springs and sports products to military applications," Johnson said.

"Together with earlier published work on this topic, the new paper illustrates that atomic diffusion in these liquids is a very complex phenomenon involving more than one type of mechanism," he said. "The NMR work illustrates that atomic motion of beryllium atoms occurs by at least two different mechanisms."

Experiments designed by Johnson have been carried out on liquid alloys aboard two space shuttle flights. He also has patented a five-metal alloy that is stronger than steel or titanium and written about the materials' armor-piercing potential.

His alloy has been used to make golf club heads, for example, that drive golf balls longer and straighter than older clubs. The new club heads allow that because almost 100 percent of the energy involved is transferred to the ball rather than a lower percentage due to more energy being absorbed by standard metals.

The U.S. Army Research Office, National Science Foundation and the U.S. Department of Energy supported the research.

http://www.sciencedaily.com/releases/1999/11/991112070246.htm

Engineers Uncover Factors That Control Ion Motion In Solid Electrolytes

To build a better jet engine, Johns Hopkins University engineer Kevin Hemker, believes you have to start small. Very small.

Hemker is starting with a powerful new microscope that allows him to see how rows of atoms are arranged in metal alloys. Knowing how these atoms arrange themselves, he says, can help predict how well these materials will be able to withstand the high temperatures, centrifugal forces and corrosive gases that exist inside a jet engine. By looking at defects in the geometric patterns formed by atoms, Hemker and his students are collecting information that may someday help scientists use a computer to devise durable new aerospace materials.

"The U.S. Air Force and others in the aviation industry want to be able to predict in a computer how well new metal alloys will behave without having to physically cast these alloys and test them," says Hemker, an associate professor of mechanical engineering in the G.W.C. Whiting School of Engineering. "That's a time-consuming and expensive process. What we're doing is providing the benchmarks that will help them get to the point where they can evaluate these new materials by using computer models."

To advance this line of research, Hemker is using a $1.3 million high-resolution transmission electron microscope recently installed at Johns Hopkins' Homewood campus. The state-of-the-art instrument, one of a handful in use at universities throughout the United States, uses a field emission gun to send a powerful beam of electrons through a very thin foil. This foil has been ground and polished to a height of less than 100 atoms. The electron beam travels through it, producing pictures of the atomic structure that can be viewed on a phosphorescent screen, captured on film or videotape, or preserved as digital information.

"Not only can we take pictures of what the microstructure looks like, we can do more complicated chemical analyses," says Hemker. "You can take the electrons that come through the specimen and pass them through an imaging filter that analyzes how much energy the electrons lost as they passed through the specimen. Electrons lose different amounts of energy as they run into different types of atoms, so this is one way you can tell what kind of atoms are present in the specimen and where they are located on a near-atomic scale."

In his own research, funded by the Air Force, Hemker is using the high-tech tool to study imperfections in the atomic structure of pure metals and intermetallic alloys ."It's the imperfections and defects in the crystal structure that control the metal's mechanical properties, such as strength and toughness," he says.

Johns Hopkins researchers are collaborating with Northwestern University scientists, who are developing computer models to predict how the properties of new materials might change as different metals are mixed into the recipe. By directly observing the arrangement of these atoms, Hemker will help determine whether these computer models are valid. Eventually, such models may be used to design new aerospace materials.

Hemker is one of at least two dozen Johns Hopkins faculty members from many science and engineering departments who are anxious to conduct experiments with the new high-resolution electron microscope. He and David Veblen, a professor in the Department of Earth and Planetary Sciences, in the Krieger School of Arts and Sciences, obtained grants to purchase the microscope and supervised its installation. Primary funding came from the National Science Foundation and the W. M. Keck Foundation.

In addition to Hemker and Veblen, Johns Hopkins researchers in chemistry, physics, environmental engineering, biomedical engineering, chemical engineering and materials science will use the new instrument to study diverse specimens, ranging from water and soil pollutants to mineral crystals, nanostructured materials and amorphous and crystalline alloys.

"This will be an invaluable tool for a wide range of research projects throughout the university," Hemker says. "We'll be able to collect structural information and chemical characterizations at the atomic scale. If we want to stay at the cutting edge of science and engineering, we had to have this microscope."

http://www.sciencedaily.com/releases/1999/04/990414060349.htm

New Alloy May Hold Key To Safer Disposal Of Spent Nuclear Fuel

John DuPont, professor of materials science and engineering and principal investigator on the project, said that a nickel-based alloy with added gadolinium showed far greater ability than any other alloy to absorb the deadly radioactive neutrons emitted by nuclear waste.

DuPont's research group included scientists from Sandia National Laboratory and Idaho National Laboratory, as well as David Williams, vice provost for research and Harold Chambers Senior Professor of materials science and engineering.

The researchers found that the gadolinium-nickel alloy passed an important test--it can be fabricated in large quantities using conventional ingot metallurgy and fusion welding techniques.

The Yucca Mountain controversy

The group's discovery, announced in an article in the December 2004 issue of the American Welding Society's Welding Journal, caps a four-year study funded by the U.S. Department of Energy's (DOE) Spent Nuclear Fuel Program.

The article, titled "Physical and Welding Metallurgy of Gadolinium-enriched Austenitic Alloys for Spent Nuclear Fuel Applications--Part II," won the welding society's Warren F. Savage Award for advancing the understanding of welding metallurgy.

The article comes amidst a controversy over plans by the Bush Administration and Congress to transport the nation's spent nuclear fuel to Nevada and deposit it inside Yucca Mountain about 90 miles northwest of Las Vegas.

In 2002, over the objections of Nevada Gov. Kenny Guinn, President Bush signed into law a resolution passed by Congress approving Yucca Mountain as the storage site for the nation's spent nuclear fuel.

DOE's application for a license to build the project is pending before the federal Nuclear Regulatory Commission. The state of Nevada, contending that the Yucca Mountain project is environmentally and geologically unsafe, has filed lawsuits against DOE, NRC, Bush and former DOE Secretary Spencer Abraham.

Passing the test

Gadolinium, a silvery-white metal, occurs naturally in several different minerals. The research conducted by DuPont's group demonstrated that gadolinium can be added to specific nickel alloys and retain its malleability and ductility, as well as its ability to be heat-treated, shaped and fabricated readily into a desired shape.

More importantly, DuPont says, gadolinium has a neutron-absorption cross- section of 48,800 barn units, more than 60 times greater than the 765-barn cross-section for boron. (Cross-section, the measure of the probability of an interaction between a particle and a target nucleus, is expressed in barn units, with one barn equal to 10-24 cm2.) Borated stainless steel is the material commonly used in conventional nuclear-waste containers. However, borated stainless steel is not capable of housing some of the nation's highly radioactive spent fuel, DuPont says.

The higher neutron-absorption capacity of gadolinium, says DuPont, means that highly radioactive fuel can now be safely transported and stored at a permanent facility.

DuPont's group conducted laboratory tests to determine the optimum amount of gadolinium to add to the nickel-based alloy. The tests involved mixing the constituent elements of the alloy, heating and melting the mixture, and allowing it to cool and solidify. The alloy was then heated and rolled into half-inch-thick sheets, and subjected to strength and ductility tests.

"We designed and developed various alloys to determine the quantity of gadolinium that could be added while still maintaining the desired properties," says DuPont. "We needed to be able to heat-treat the final material, weld it and fabricate it."

A specification has been approved for the alloy by ASTM (the American Society of Testing Materials), which sets technical standards for materials, products, systems and services. The alloy is being reviewed by the American Society of Mechanical Engineers, which also sets standards for the use of new products. Neutronics (neutron-absorption) tests on the alloy were performed at Lawrence Livermore National Laboratory in California.

The research team was awarded a U.S. patent for the alloy last year.

Prior to its work with the gadolinium-nickel alloy, the researchers spent a year investigating gadolinium-enriched stainless-steel alloys for spent nuclear fuel storage applications before coming up against major obstacles to the production of those alloys using conventional hot working techniques.

http://www.sciencedaily.com/releases/2005/05/050513224446.htm

Los Alamos Pressure Process Makes Pure Zirconium Glass

Zirconium may not be a girl's best friend, but by squeezing the metal with roughly the same pressure needed to make diamonds, scientists at the University of California's Los Alamos National Laboratory made a pure glass that may prove nearly as valuable as real diamonds.

The pure metallic glass formed by their high-pressure method holds promise for stronger, more stable materials for medical, sports and electronic products.

Yusheng Zhao and Jianzhong Zhang, both from Los Alamos' Lujan Neutron Scattering Center, have found that pure zirconium metal forms glass at temperatures roughly one-third of zirconium's melting temperature and static pressures around five billion pascals, or more than 50,000 times atmospheric pressure. They published their findings in the July 15 edition of Nature.

"This is the first time that bulk metallic glass has been formed from a single element or pure metal," Zhao said. "By using industrial pressure processes to make pure samples without the defects that appear in metallic glasses made the conventional way, we've identified a method with potentially important commercial applications."

Bulk metallic glasses have found more and more uses in the past 15 years or so, and have begun replacing some conventional materials such as crystalline metals, metal alloys and high-tech ceramics. Among current applications are structural engineering materials, consumer electronic components, jewelry, replacement joints and skis, tennis rackets, golf club heads and other gear that requires lots of rebound.

Although novel, bulk metallic glasses are highly desirable. They resist breaking when stretched, they keep their shape and they are hard to shatter. In scientific terms, they possess high elastic strain limit, high yield strength and fracture toughness. They behave elastically like polymers but are much stronger than metal alloys, characteristics that make them ideal for structural engineering materials and many other applications.

But all the bulk metallic glasses contain three or more component elements, which means they have lower thermal stability and phase separation at high temperatures, Zhao said.

"We've broken with the conventional wisdom that BMGs can only be produced from multicomponent alloys and only with the conventional approach of melting and fast quench," he explained.

Zhao said one of the most remarkable characteristics of the amorphous or glass zirconium they produced is its thermal stability. The Los Alamos samples remain as glass at temperatures above 1,600 degrees Fahrenheit - more than 400 degrees higher than the temperatures at which they were formed - and pressures of 2.8 billion pascals. Traditional BMGs turn to crystals, and thus lose many important properties, at temperatures as low as 800 degrees F.

Zhao and Zhang used a large-volume press to produce samples of millimeter size, but the relatively low pressure and temperature range allows them to make samples of up to an inch, so their process could be scaled up to industrial conditions. Some previous high-pressure experiments used diamond-anvil cells to form amorphous phases from other crystalline materials, with much smaller sample sizes of a few thousandths of a millimeter.

"One of the key reasons for the success of our experimental method was the high purity of the polycrystalline zirconium metal that we were given by our colleagues Paulo Rigg and Rusty Gray," Zhao said. "We worked with them on zirconium equation of state studies at high pressures and temperatures, as well as phase diagram studies."

Much remains to be learned about the new class of pure glass. Zhao and Zhang have tried to duplicate their experiments with commercial-grade zirconium, but found that higher temperatures and pressures were needed to make the glass, and it didn't retain its characteristics when pressures and temperatures returned to normal. They plan follow-up experiments to try to solve this dilemma.

All the experimental work took place at Los Alamos Neutron Science Center's HIPPO flight path, and the synchrotron X-ray beam lines at Argonne and Brookhaven national labs. The Lujan Center is supported by the U.S. Department of Energy's Basic Energy Sciences program. Funding of early work on pressure forming of bulk glass alloys came from the internal Laboratory Directed Research and Development program.

http://www.sciencedaily.com/releases/2004/07/040721085619.htm

Nanoparticles "Tailor" Complex Fluids For Photonics, Ceramics Applications

Colloidal suspensions are complex fluids utilized in numerous applications ranging from advanced materials to drug delivery. Controlling the stability of these fluids can influence such characteristics as flow behavior, structure and mechanical response, and may result in materials with improved optical and electrical properties.

As reported in the July 31 issue of the Proceedings of the National Academy of Sciences, Jennifer Lewis and her colleagues have devised a process that they call nanoparticle haloing. This self-organizing process imparts stability to otherwise attractive colloidal microspheres by decorating regions near their surface with highly charged nanoparticles.

"Using this nanoparticle haloing approach, we can control the phase behavior and structure of materials assembled from colloidal systems," said Lewis, a UI professor of materials science and engineering and of chemical engineering. "Our approach complements traditional stabilization techniques, such as electrostatic stabilization, by allowing systems of negligible charge or high ionic strength to be stabilized."

Tailoring the interactions between particles allows the researchers to engineer the desired degree of colloidal stability into the mixture.

"That means we can create designer colloidal fluids, gels and even crystals," Lewis said. "Our ability to control colloidal forces and phase behavior depends not only on the charge of the nanoparticles, but also on their size. Through nanoparticle engineering, we can assemble structures with properties that would not be possible through traditional stabilization routes."

For example, Lewis has teamed up with co-author Paul Braun, a UI professor of materials science and engineering, to explore the use of these nanoparticle-stabilized colloidal microsphere mixtures in assembling robust periodic templates for photonic band gap materials. The researchers recently were awarded funding by the National Science Foundation to pursue such efforts.

Lewis and her students are also studying the structure and flow behavior of colloidal fluids and gels assembled from these microsphere-nanoparticle mixtures. By compositionally modulating interparticle forces, the researchers can produce systems whose properties vary dramatically. Such studies provide the foundation of ongoing efforts in the area of colloidal processing of electrical ceramics.

In addition to Lewis and Braun, the research team included UI doctoral students Valeria Tohver and James Smay, and Carnegie Mellon University graduate student Alan Braem. The National Aeronautics and Space Administration Microgravity Research Program funded the work.

http://www.sciencedaily.com/releases/2001/08/010802081132.htm

Researchers Find Way To Minimize Evolution Of A Toxic Gas

Science Daily — HOUGHTON, MI--Michigan Tech researchers have found a way to reduce the evolution of toxic gas from ferrosilicon.

Dr. Claudia Nassaralla and Dr. Richard Heckel, professors of metallurgical and materials engineering, spent four years studying the process that controls the development of phosphine gas in ferrosilicon.

"Ferrosilicon alloys are important materials for the steel industry because they are used as de-oxidants and alloying additions in the production of steels used in the manufacturing of transformers and electric motors" says Nassaralla. But when ferrosilicon alloys are exposed to water and water vapor during transportation to steel mills and prior to the steelmaking process, they evolve phosphine gas which smells like garlic and rotten fish and is toxic. Phosphine has been blamed for several accidents in the early 1900's, and at that time many people died from exposure to it. The most recent accident with fatalities was reported in 1997 in Japan. It occurred in a Chinese cargo ship transporting an inferior quality ferrosilicon.

The process that controls phosphine gas evolution in ferrosilicon is directly related to the presence of specific impurity phases in the alloys, Nassaralla says. The MTU team found a relationship between the evolution of phosphine gas and the presence of reactive phosphide forming elements in ferrosilicon---- especially aluminum, calcium, magnesium and phosphorus. They discovered that suppressing the formation of the reactive phosphide phases in ferrosilicon alloys can reduce the evolution of phosphine gas.

The MTU study has shown that "a chemically inactive phosphide phase can be formed by adding the appropriate alloying elements to the ferrosilicon alloy," Nassaralla explains. The MTU research team found that phosphine gas evolution can be dramatically reduced when sufficient amounts (10 percent or more) of magnesium are added.

Nassaralla believes that this technique "could have a significant economic impact for the producers and consumers of ferrosilicon alloys, as well as improve the safety of its handling and transportation."

The project is being funded by a grant from the Norwegian Ferroalloy Producers Research Organization.

http://www.sciencedaily.com/releases/1999/04/990412074305.htm

Developing Flexible Metal Composite

Science Daily — Researchers at the University of California, San Diego (UCSD) Jacobs School of Engineering have received a $2.5 million Multidisciplinary University Research Initiative (MURI) grant to develop and test a metallic composite material capable of changing shape and then returning to its original form. The research is funded by the Office of Naval Research and may have applications for ships, submarines, and other vehicles and structures.

The use of shape memory alloys is very attractive because it enables large global recoverable, super-elastic deformations of up to six percent, a ten-fold over conventional elastic response. We hope to elicit even greater super-elastic performance by creating a hybrid composite alloy material" says Sia Nemat-Nasser, director of the Center of Excellence for Advanced Materials and principal investigator for the project.

Although shape-memory alloys have been around for over 30 years, Nemat-Nasser and his colleagues are adding a new spin by combining them with other non-metallic materials. He is working with Kenneth Vecchio, a professor of materials science at the School, and representatives from Caltech and the University of Washington, to use plates of shape-memory nickel-titanium (Ni-Ti) to sandwich shape-memory, super-elastic foams and rods embedded with hollow glass beads.

"This unique combination should allow for even greater flexibility and resilience in a very lightweight structure," explains Nemat-Nasser. "The hybrid material should provide optimal energy absorbing capability against high-velocity projectile impact, explosion-induced shock, or other dynamic events." In other words, the absorbing capability, in conjunction with the material's flexibility, could enable it to stop cracks and collateral damage by distributing the forces from impact.

To test the new alloy composite, Nemat-Nasser and his coworkers will use a variety of devices, including a full complement of novel Hopkinson bars, gas guns, high-speed cameras, and high-speed X-ray machines, as well other common materials processing and characterization equipment.

http://www.sciencedaily.com/releases/2002/07/020715075621.htm

Easing Concerns About The Toxicity Of Diamond Nanoparticles

Liming Dai (University of Dayton), Saber M. Hussain (Wright-Patterson Air Force Base) and colleagues, including PhD student Amanda Schrand, explain that advances in technology have made a new generation of nanodiamonds available. Although diamond in bulk form is inert and biocompatible, nano-materials often behave differently than their bulk counterparts. That led to concern that diamond nanoparticles might have toxic effects on cells.

"We have for the first time assessed the cytotoxicity of nanodiamonds ranging in size from 2 to 10 nm," the researchers state, adding that nanodiamonds were not toxic to a variety of different cell types.

"These results suggest that nanodiamonds could be ideal for many biological applications in a diverse range of cell types," they add.

http://www.sciencedaily.com/releases/2007/01/070101113457.htm