A Japanese company has developed what it claims is the first commercial technology for producing regular, uniform nanoparticles to a specified size and shape. Tokyo-based Shimura Kako, once a leading nickel smelter, is using the Nanomizer, a technology acquired through a deal with R&D company San-Ei Kasei, to produce particles of a range of metals in the size range 1-300 microns. Applications for the particles include everything from catalytic converters to microchips, with a deal being done at the end of last year with Hitachi Maxell to use the technology for making improved computer hard disc drives.
The Nanomizer Process
The Nanomizer is essentially a large brass crucible or chamber into which molten metals are poured to create the tiny particles. The special atmosphere that is developed inside the chamber using proprietary technology causes this conversion - gases are spun at high speed and the metal particles are formed in the region of zero centrifugal force. Of course, there is more to the Nanomizer than this, but `the details are being kept secret. According to Shigenobu Sekine, inventor of the Nanomizer, the system enables the production of a metal powder that is spherical and of an equal size between 1-300 microns: By changing the conditions, the size and even the shape of the particles can be accurately controlled if required. The Nanomizer can also be used to create thin elliptical flakes of a material. All metals can be used, in theory, but so far only those with melting points of less than 1800°C have been successfully processed.
Microstructural Control Using the Nanomizer Process
The microstructure of the particles produced by the Nanomizer can also be varied with different processing conditions. Porous, crystalline and amorphous particles can be produced, allowing different types of particles to be produced for different applications. For example, the porous particles may be of use for making catalytic converters, while the crystalline particles could be used for manufacturing magnets. A further benefit is the possibility of combining metals consistently to form alloys and intermetallic compounds. According to Sekine, ‘While we know there are other companies working on nanoparticle production worldwide, none of them have been able to produce particles with the unique properties and commercial advantages that the Nanomizer enables: Professor Niihara, an expert in nanoparticle technology and Director of the Research Centre for Intermaterials at Osaka University, says, ‘The Nanomizer is at present the best method of mass producing micron-sized spherical metal particles and the potential applications and possibilities of creating new metals is extremely exciting:
The NSK Supermagnet
One important new application of particles produced by the Nanomizer is the so called NSK60 ‘supermagnet’, which Shimura Kako says is significantly more powerful than conventional magnets thanks to the finely controlled microstructure. The Nanomizer breaks down the neodymium, iron and boron that are used to form the magnet to make super-fine spherical particles. These are then compressed into blocks and magnetised, to give a very powerful magnet. The superfine particles can also be used in a plastic injection moulding process to make plastic bonded magnets of a variety of shapes. A further advantage of the NSK60 is that it does not rust, as the magnetic crystalline grains are already coated by an extremely thin oxide later following Nanomizer processing. Applications of the new magnetic material could include more powerful electric motors and longer-lasting ‘super-batteries’, which could make the concept of an all-electric car much more viable. Overall, a study by the then-named Andersen Consulting showed a potential global magnet market of $5 billion.
Nanomizer Materials in Hard Disk Drives
The deal between Shimura Kako and Hitachi Maxell paves the way for another large scale application of the products of the Nanomizer. The companies are aiming to commercialise the technology for the hard disc drive market, to produce much faster devices than those currently available. The tiny particles would be magnetised and suspended in a thin oil, to reduce friction as the hard disc rotates. Once suspended, the Nanomized particles will maintain their positions, according to the companies, rather than clumping together and heating up. This allows the speed of the drive to be increased without creating additional friction.
Other Potential Applications for Nanomizer Materials
Other potential applications for particles produced by the Nanomizer include an ‘ink’ for printing even smaller, more detailed circuits for the next generation of microchips, new materials for efficient catalytic converters, high speed micro-bearings, fuel cells, micromachines and nanotools, optical displays, filters, and environmental sensors.
Sekine claims that the particles don’t cost any more than those produced by other methods, as the Nanomizer allows a throughput of 2kg per minute for eight hours continuously, thereby making it a highly commercial technology. With the technology enabling the economic production of any quantity of particles, along with its versatility in producing such a wide range of tailor-made particles, the Nanomizer seems like a system with a big future for its tiny products.