subject: Three Types Of Ultra Fine Metal Powders [print this page] Ultrafine metal particles can be divided into third gear: big, small and ultra-fine particles. Large ultra-fine particle size is from 100A to 1000A. The medium ultrafine particles size is from 20A to 100A and the ultrafine particles diameter is below 20A.
Finer particle size of ultrafine metal particles is, the more significant melting point reduces. Lower melting point, the lower the temperature of metal, alloy or compound powders sintering, obtained a variety of mechanical components, not only save energy, reduce the difficulty of the manufacturing process and, more importantly, the performance components. Such as high melting point materials WC, SiC, BN,, Si3N4 is used as a structural material, the manufacturing process requires high temperature sintering, when the use of ultrafine particles in a very low temperature, and without additives for high-density sintered body. These high-performance inorganic structural materials open up a wider and wider application through a very good practical significance.
The smaller the diameter of the ultrafine particles, it is better than the greater surface area, surface to a corresponding increase in the high chemical activity. It can be used for efficient catalyst for chemical reactions, can be used for rocket solid fuel combustion additives. Existing practice shows that a catalyst made of ultrafine particles of Ni and Cu-Zn alloy as the main ingredient in the efficiency of the organic hydride is 10 times that of conventional catalysts. Adding less than 1% of the weight of the solid rocket fuel. ultra-fine particles of aluminum powder or nickel powder.The calories of every gram of fuel are doubled.
Strong magnetic characteristics of the application of the most advanced used in magnetic materials. Using an Fe2O3 , Cr02 and metal ultrafine particles has been developed ultra-high density magnetic tapes and video with better performance with a recording density of 10 times in the past, and has good stability. Now it opens up a range of applications, such as a new type of liquid colloidal magnetic fluid materials, mechanical seals, loudspeakers, etc.
Metal powder usually seen in reflected light, showing a metallic luster, however, the metal ultrafine particles completely lose their luster and the finer the particles, the deeper black. This may be the reason of the light wave is completely absorbed. This feature, in the utilization of solar energy as a light absorbing material, but also can take advantage of its infrared absorption as a hotline detector coatings, etc. With another example of ultrafine particles of ferric oxide and zinc stearate, dispersing agent is added to the polystyrene resin made film, through the visible light, and has a very good absorbent of ultraviolet light. If it is added to plastics, anti-UV can be made of transparent plastic container, transparency is much better than the brown glass. Adding it to food packaging can protect food from ultraviolet light and effectively extend the shelf life.
The ultrafine metal powder particles are applied in catalytic, low-temperature sintering, composite materials, new functional materials, tunnel engineering, medicine and bio-engineering. It has achieved very encouraging results. The study of history of the ultrafine metal powder particles is generally from 1962. In fact, a more comprehensive research and development began in the 1980s. Generally speaking, this work is still in the research and start-up phase. There are many technical and theoretical issues which need to be further explored. No wonder scientists expect that: the ultrafine particles are a new type of functional materials in the 21st century.
