Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanopowder Consisting Of Identical Particles

01.03.2004


High-quality nanopowders made of refractory ceramics are a rare and very expensive material. All known methods of their manufacturing face the same problems - scanty quantities, extensive variety of particle sizes and expensive production. Researchers from the town of Tomsk have invented and manufactured a device to produce a choice selection of particles - all particles are equal to the required size and inexpensive. The project has been funded by two foundations - the Russian Foundation for Basic Research and the Foundation for Promotion of Small-Scale Enterprises Development in Scientific and Technological Area.



Researchers of the Tomsk State University jointly with their colleagues from the MIPOR research-and-production association have designed a device and manufactured with its help pilot lots of some nanopowders, including the silicon powder and the silicium nitride and silicon carbide powders. The project has been funded by two foundations ? the Russian Foundation for Basic Research and the Foundation for Promotion of Small-Scale Enterprises Development in Scientific and Technological Area.
The action of a new device is based on the method the researchers called ?self-abrasion?. In the device, the fluid jet captures the particles and brings them upwards to the separation zone at the velocity close to the transsonic speed. The centrifugal separator separates off the thin fraction, i.e. the smallest particles. Heavy and large particles fall back to the pounding zone. The streams meet each other, but their velocities are different: they fly up at a high speed and fall down rather slowly, along with that the layer contains the non-ground material, which is constantly poured into the device. Microwhirlwinds originate at the ?stream/non-ground material? border due to significant difference of velocities, the relative velocities of particles inside the microwhirlwinds reach 100 to 300 meters per second. The particles break to pieces blowing each other, friction polishing the particles.

First, the researchers guided by Yuri Birukov investigated the entire process with the help of the mathematical model. The researchers determined how many times each particle is to collide with others to get broken into pieces and then to get ’ground’ through to the required size and shape, what should be the device parameters and the gas velocity to get the nanopowder with predetermined characteristics at the output. Besides, in order to exclude milling of admixtures, the particles should not touch the walls of the device in the course of circulation.



"Besides mathematical modelling there exists even more important physical modelling, i.e. experimental investigation", says Yu. A. Birukov. "Experimental investigations of such complicated processes as obtaining nanopowders last for years. We have produced and tested hundreds of experimental plants within 30 years before achieving the above results."

The results achieved are powders of silicon, silicium nitride and silicon carbide, of aluminium oxide, of tungsten carbide and of titanium, aluminium, copper and tungsten, their average particle size being 0.3 mcm (300 nanometers) and 0.5 mcm (500 nanometers). They contain practically no admixtures, and the particles are very similar in size. They suit perfectly for producing various refractory components, for example turbine blades. The method is not too expensive.

Sergey Komarov | alfa
Further information:
http://www.informnauka.ru

More articles from Materials Sciences:

nachricht Cementless fly ash binder makes concrete 'green'
19.06.2018 | Rice University

nachricht Ground-breaking discoveries could create superior alloys with many applications
19.06.2018 | Chalmers University of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Carbon nanotube optics provide optical-based quantum cryptography and quantum computing

19.06.2018 | Physics and Astronomy

How to track and trace a protein: Nanosensors monitor intracellular deliveries

19.06.2018 | Life Sciences

New material for splitting water

19.06.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>