Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Discovery could bring widespread uses for ’nanocrystals’


Researchers at Purdue University have made a surprising discovery that could open up numerous applications for metal "nanocrystals," or tiny crystals that are often harder, stronger and more wear resistant than the same materials in bulk form.

The research engineers have discovered that the coveted nanocrystals are contained in common scrap, the chips that are normally collected and melted down for reuse.

"Imagine, you have all of these bins full of chips, and they get melted down as scrap," said Srinivasan Chandrasekar, a professor of industrial engineering. "But, in some sense, the scrap could be more valuable pound-for-pound than the material out of which the part is made."

Nanocrystals might be used to make super-strong and long-lasting metal parts. The crystals also might be added to plastics and other metals to make new types of composite structures for everything from cars to electronics.

However, nanocrystals have been far too expensive and difficult to produce to be of any practical industrial or commercial use. The cost of making nanocrystals is at least $100 per pound, while nanocrystals of certain metals critical to industry cannot be made at all with present laboratory techniques, said Chandrasekar and Dale Compton, also a professor of industrial engineering at Purdue.

"Our contribution has been in developing a process that we think can be used to make these materials in large quantities at very low cost," Chandrasekar said. "The cost is expected to be no more than $1 per pound, plus the initial cost of the bulk material."

Findings will appear in the October issue of the Journal of Materials Research, published by the Materials Research Society. The paper was written by Travis L. Brown and Srinivasan Swaminathan, graduate students in Purdue’s School of Industrial Engineering, Chandrasekar and Compton, Alexander King, head of the School of Materials Engineering, and Kevin Trumble, a professor in the School of Materials Engineering.

One process now used to make nanocrystals in research labs involves heating a metal until it vaporizes and then collecting nanocrystals as the vaporized metal condenses onto a cold surface.

"The process is cumbersome, and if you want to make a pound of the material, or a few hundred pounds, it’s time-consuming," Chandrasekar said. "There are other techniques, but all of them have serious limitations."

Chandrasekar and Compton have discovered that the chips left over from machining are either entirely or primarily made of nanocrystals. The chips, which are shaved away from metals as they are machined, ordinarily are collected as scrap, melted down and reused. But melting down the chips turns nanocrystals back into ordinary bulk metals, removing their super strength, wear resistance and other unusual properties.

These chips, then, might be saved and processed for use in a wide range of products. Metal nanocrystals might be incorporated into car bumpers, making the parts stronger, or into aluminum, making it more wear resistant. Metal nanocrystals might be used to produce bearings that last longer than their conventional counterparts, new types of sensors and components for computers and electronic hardware.

Nanocrystals of various metals have been shown to be 100 percent, 200 percent and even as much as 300 percent harder than the same materials in bulk form. Because wear resistance often is dictated by the hardness of a metal, parts made from nanocrystals might last significantly longer than conventional parts.

"One of the really big advantages of this is that you can do it with almost any material," Compton said. "You can make nanocrystals of steels, tungsten, titanium alloys, nickel alloys."

The engineers have measured increased hardness in nanocrystals of copper, tool steel, stainless steel, two other types of steel alloys and iron.

"We have a lot of data demonstrating that these materials are nanocrystalline and that they have enhanced mechanical properties," Chandrasekar said.

Currently, though, it is either prohibitively expensive or impossible to make nanocrystals of many alloys, including steel alloys critical to industry and commercial products.

The Purdue researchers were led to their discovery by findings in scientific literature.

"There is some work in the literature that says if you introduce very large strains into a material it will be converted into nanocrystalline," Compton said. "In our research, we knew that there was strain being introduced at the point of the cutting tool."

The very strains caused by a cutting tool also produces nanocrystals about 100 nanometers in diameter, he said.

Nano is a prefix meaning one-billionth, so a nanometer is one-billionth of a meter, which is roughly 10 atoms wide.

Nanocrystals are not currently used to make products. However, experimental uses for nanocrystals include research aimed at developing high-performance bearings, such as those used for helicopter rotors; creating new types of high-strength, lightweight composite materials; making superior fuel-injection components for diesel engines; and producing new types of chemical catalysts.

Further research will be needed to determine whether the nanocrystals contained in scrap chips retain their desired properties after standard processing steps. Those steps include milling the chips to make powders and then compressing and heating the powders to make metal parts. Nanocrystals currently produced in laboratories have been subjected to such processes, and they have retained their nanocrystalline properties, the engineers said.

Purdue has filed a patent application. The work has been funded by private donations and the Trask Pre-Seed Venture Fund, originally established in 1974 through an estate gift from Vern and Ramoth Trask, both Purdue alumni.

Writer: Emil Venere, (765) 494-4709,
Sources: Dale Compton, (765) 494-0828,
Srinivasan Chandrasekar, (765) 494-3623,
Purdue News Service: (765) 494-2096;

Emil Venere | EurekAlert!
Further information:

More articles from Process Engineering:

nachricht Intelligent wheelchairs, predictive prostheses
20.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

nachricht Jelly with memory – predicting the leveling of com-mercial paints
15.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>