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.
Sergey Komarov | alfa
Scientists announce the quest for high-index materials
24.07.2017 | Moscow Institute of Physics and Technology
ADIR Project: Lasers Recover Valuable Materials
24.07.2017 | Fraunhofer-Institut für Lasertechnik ILT
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
24.07.2017 | Power and Electrical Engineering
24.07.2017 | Materials Sciences
24.07.2017 | Materials Sciences