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1、纳米材料（Nanometer material）brief introductionFrom the size, usually produce significant changes in physical and chemical properties of fine particles in the size of 0.1 microns (1 m = 100 cm, 1 cm = 10000 micron, 1 micron = 1000 nm, 1 nm = 10 angstroms), 100 nm. Therefore, particles with a particle siz
2、e of 1100 nm are called ultrafine particles, and they are also nano materials. Nano metal materials were developed in the middle of 1980s, and later came out with nano semiconductor films, nano ceramics, nano porcelain materials and nano biomedical materials. Nano structured materials, referred to a
3、s material (nano), refers to the size of their structural units between 1 nm and 100 nm range. Because its size is close to the coherence length of electrons, its properties change greatly because of the self-organization caused by strong coherence. Also, the scale is close to the wavelength of ligh
4、t, it has special effect of the surface, so its performance characteristics, such as melting point, magnetic, optical, thermal, electrical conductivity and so on, are often different in nature of the substance in the overall state of the. Nano particle materials, also known as ultrafine particles, a
5、re composed of nanoparticles (nano, particle). Nanoparticles also called ultrafine particles, generally refers to the particles in the 1 100nm between the size of the transition region is at the junction of atomic clusters and macroscopic objects, usually from on microscopic and macroscopic point of
6、 view, macro system micro system the system is not only the atypical atypical, is a typical mesoscopic system, it with surface effect, small size effect and macroscopic quantum tunneling effect. When people will be subdivided into macroscopic objects of ultrafine particles (nano), it will show many
7、unique properties, it is compared with the optical, thermal, electrical, magnetic, mechanical and chemical properties and bulk solids have significantly different will. The broad range of nanotechnology can include nano material technology and nano processing technology, nano measurement technology,
8、 nano application technology and so on. The nano technology focuses on nano functional material production (superfine powder, coating, nano modified materials etc.), performance testing technology (chemical composition, microstructure, surface morphology, physical and chemical, electrical, magnetic,
9、 thermal and optical properties). Nanofabrication technology includes precise machining technology (energy beam machining) and scanning probe technique. Nano materials have unique properties, when the material of small scale to a certain extent, it must use quantum mechanics to replace the tradition
10、al mechanical view to describe its behavior, when the powder particle size from 10 micron to 10 nm, the diameter is changed to 1000 times, but converted into volume will be 10 the power of 9 times, so the two act will produce significant differences. The reason that nanoparticles differ from bulk ma
11、terial is that its surface area is relatively large, that is, the surface of ultrafine particles is covered with a ladder like structure, which represents unstable atoms with high surface energy. These atoms are very easy to bond with foreign atoms and provide large surface active atoms because of t
12、heir reduced size. On the melting point, the powders because each particle composed of atoms, the surface atoms are in the unstable state, so that the surface lattice vibration amplitude is large, so it has high surface energy, heat caused by the special properties of ultrafine particles, which is c
13、aused by the melting point decreased with nano powder than traditional powder in a relatively easy low temperature sintering, and become a good sintering promoting material. The common magnetic material are more magnetic area aggregate, when the particle size as small as the area cannot separate mag
14、netic zone is formed of single domain magnetic material. Therefore, when the magnetic material is made into ultrafine particles or films, it will become an excellent magnetic material. The particle size of nanoparticles (10 nm to 100 nm) is smaller than the length of light wave, so it will interact
15、with incident light very complex. Metal in the appropriate evaporation deposition conditions, can be easily absorbed light of black metal ultrafine particles, known as metal black,This contrasts strongly with the high reflectivity surface of the metal in the vacuum coating. Nanomaterials can be used
16、 in infrared sensor materials because of their high light absorptivity. Nanotechnology is still in its infancy in countries all over the world. Although a few countries, such as the United States, Japan and Germany, have begun to take shape, they are still under study. The emergence of new theories
17、and technologies is still in the ascendant. Our country has made great efforts to catch up with the advanced countries, and the research team is also growing. 1Edit the discovery of this materialThe material particles that make up the material become smaller. Can the little be different from the big
18、 man in nature? This is the discovery of nanomaterials, the German physicist Grant (Grant) scientific thinking. It was a day in 1980, when he traveled to Australia, and when he drove alone across the great desert of Australia, the empty, lonely and lonely surroundings made his thinking particularly
19、active and acute. He has been engaged in the study of crystal materials for a long time to understand that the grain size of crystals has a great influence on the properties of materials: the smaller the grain, the higher the strength. The idea above was only a general rule of material, and his idea
20、s went gradually step by step: what would the material be like if the grain of the material that was made up of the material was only a few nanometers in size? There may be some earth shaking changes! When he returned home with these ideas, he began experimenting immediately. After nearly 4 years of
21、 hard work, superfine powders containing only a few nanometers were produced in 1984, including ultrafine powders of various metals, inorganic compounds, and organic compounds. Gretel discovered a very interesting phenomenon when he studied the ultrafine powders. As everyone knows, the metal has a v
22、ariety of different colors, such as gold, gold, silver and silver, iron is black. As for other metal materials such as inorganic compounds and organic compounds, they can also bring a different color: porcelain glaze above is always colorful, composed of various organic dyes is very bright. But once
23、 all these materials have been made into ultrafine powders, their colors are invariably Black: glazes, dyes, and various metals on the porcelain all turn into a color black. As he imagines, little difference has undergone a dramatic change in performance compared with the big man. Why, no matter wha
24、t material, once made into nano small, it has become black? It turns out that when the particle size of the material becomes smaller than the wavelength of the light (about 1 * 10m), the reflectivity of the material becomes very low, about as low as 1%. Since the reflection of ultrafine powders on l
25、ight is very small, the nano materials we see are all black. The changes in the little nature are truly incredible. Argonne National Laboratory for famous prepared nanometer metal, the metal conductor from actually become an insulator; ceramic ceramic powder and sintered nano size will not fall on t
26、he break. Wrights discoveries have been and are changing some of the traditional concepts in science and technology. Therefore, nano materials will be a high-profile high-tech products in twenty-first Century.Edit this paragraph nanostructureNano structure is a new system based on the material unit
27、of nanometer scale and constructed or constructed according to certain rules. It includes nano array, mesoporous assembly system, film mosaic system. At present, the research of nano array system is focused on the two bit system formed by the arrangement of metal nanoparticles or semiconductor nanop
28、articles on an insulating substrate. The nanoparticles and mesoporous solid assembly system due to the characteristics of the particles themselves, as well as the matrix and coupling interface produced some new effects, has become the research hotspot, according to which type of support can be divid
29、ed into inorganic mesoporous composite polymer and mesoporous composite two categories,Depending on the state of the support, it can be divided into ordered mesoporous complex and disordered mesoporous complex. In the film mosaic system, mainly studies on the nanoparticle film is launched electrical
30、 and magnetic properties of the system based on the. Scientists in the United States by self assembly technology, hundreds of single walled carbon nanotubes composed of crystal cable Ropes, this has the characteristics of metal rigging, room temperature resistivity is less than 0.0001 /m; the three
31、nanometer lead iodide assembled into nylon -11, with photoconductivity of the X ray, the use of the performance for the development of digital radiography photography foundation.Edit the technical specifications of this paragraphNano alumina appearance white powder. Nano alumina; crystal phase; gamm
32、a phase. The average particle size of nano alumina (nm) is 20 + 5. nm, and the content of alumina is more than 99.9%. Melting point: 2010 DEG C, -2050 DEG C, boiling point: 2980 DEG C, relative density (water =1): 3.97-4.0Edit the scope of this paragraphThe natural nano material turtle lays eggs on
33、the coast of Florida, but the young turtles are able to survive and grow in order to find food and swim near the sea. Finally, the growing turtle returns to spawning on the beach in Florida. It takes about 56 years to go back and forth. Why can a turtle walk thousands of kilometers? They rely on nan
34、o magnetic material in the head to navigate accurately. When biologists study why dove, dolphins, butterflies, bees and other creatures never lose their way, it is also found that there are nanomaterials in these organisms that navigate them. Most of the nano magnetic materials used in practice are
35、made of artificial materials. Nano magnetic material has very special magnetic properties, nanoparticles with small size, single domain structure and coercivity properties is very high, it is made of magnetic recording materials not only sound, image and good signal-to-noise ratio, and recording den
36、sity dozens of times higher than gamma -Fe2O3. Superparamagnetic strong magnetic nanoparticles can also be made into magnetic liquids, used in electroacoustic devices, damping devices, rotary seals and lubrication, and beneficiation. Nano ceramic materials, the traditional ceramic materials, the gra
37、in is difficult to slide, the material is brittle and the sintering temperature is high. The grain size of nano ceramics, grain easily in other grain sports, therefore, nano ceramic materials with high strength and high toughness and good ductility, these properties make nano ceramic material for co
38、ld working at room temperature or under high temperature. If the nano ceramic particles forming in high temperature, and surface annealing treatment can make nano materials become a conventional ceramic material to keep the surface hardness and chemical stability, high ductility and internal propert
39、ies of ceramic nano material still has. Nano sensors, nano two zirconia, nickel oxide, titanium dioxide and other ceramics are sensitive to temperature changes, infrared rays and automobile exhaust. Therefore, they can be used to make temperature sensors, infrared detectors and automobile exhaust ga
40、s detectors. The detection sensitivity is much higher than that of the common ceramic sensors. In the aerospace hydrogen oxygen engine, the inner surface of the combustion chamber needs high temperature, and its outer surface should be contacted with coolant. Therefore, the inner surface should be m
41、ade of ceramic, and the outer surface should be made of metal with good thermal conductivity. But massive ceramics and metals are hard to mix together. If you make between metal and ceramic production of its components gradually varied continuously, metal and ceramic acommunity, finally can be combi
42、ned together to form functionally gradient material, it means the composition change like a sloping ladder. When the metal and ceramic nanoparticles are mixed and sintered in accordance with the requirement of the gradual change of the content, the heat resistance of the combustion chamber inside th
43、e furnace can be reached and the outer side has good thermal conductivity. The nano semiconductor material silicon, gallium arsenide semiconductor materials made of nano materials, with many excellent properties. Such as,The quantum tunneling effect in nano semiconductor leads to the anomalous elect
44、ron transport and conductivity of some semiconducting materials, and the thermal conductivity decreases with the decrease of particle size, even negative value. These characteristics play an important role in large-scale integrated circuit devices, optoelectronic devices and other fields. A new type
45、 of solar cell with high photoelectric conversion efficiency, which can work normally even in rainy days, can be prepared by using semiconductor nanoparticles. Because of the nano semiconductor particles by light irradiation of electrons and holes with strong reduction and oxidation ability, so it c
46、an oxidize toxic inorganic substances, most degradation of organic matter, generates non-toxic and odorless carbon dioxide and water, therefore, can make use of semiconductor nanoparticles using solar photocatalytic decomposition of organic and inorganic compounds. The nano catalytic material of nan
47、oparticles is an excellent catalyst, which is due to the surface of the nanoparticles with small size, large volume fraction, the inside surface of the chemical bonding state and electron states and particles of different surface atoms, the coordination is not complete, resulting in surface active s
48、ites increased, so it has the basic conditions as a catalyst. The nanoparticles of nickel or copper zinc compounds are excellent catalysts for hydrogenation of certain organic compounds and can be used as an alternative to expensive platinum or palladium catalysts. Nano platinum black catalyst can r
49、educe the temperature of ethylene oxidation reaction from 600 to room temperature. The medical application of blood red blood cells in the size of 6000 9000 nm, while the nanoparticles of only a few nanometers in size, in fact than the red blood cells are much smaller, so it can move freely in the blood. If a variety of therapeutic nanoparticles are injected into various parts of the human body, they can be examined for lesions and treatment, and the effect is better than the traditional injection and medication. 9 nano