New developments in several hot areas of nanomaterials

1. design and research of nano-assembly system

At present, the research object is mainly focused on the nanoarray system. Nano-mosaic system; Mesoporous and nanoparticle composite system and nanoparticle membrane. Purpose is according to the need to design a new material system, explore or improve the performance of the material, the target is the preparation for the production of nano device, such as high brightness solid electronic display, nanocrystalline diode, vacuum ultraviolet to the near infrared especially in the light of blue, green and red light control can be used to power generation and electronic luminous tube nanocrystals as main material, the international call this material “quantum” nanocrystals, have been designed in the laboratory of nano device have Si – SiO2 light-emitting diode, Si doped Ni nanoparticles light-emitting diodes (leds), The red, green and blue tunable diodes are made from CdSe of different nanometer scale. Mesoporous membrane assembly system and nanoparticles with nano assembly system is the current important research object, the main design idea is to use small particles of seepage effect, quantum size effect and according to the need of the overall performance of clipping, adjustment and control of materials to achieve the unique properties of conventional does not have this aspect of the study will be striking at the turn of the century and the next century frontier. At present, the research of nanoarray system mainly focuses on the two-dimensional system in which metal nanoparticles or semiconductor nanoparticles are arranged neatly on an insulating substrate.

In recent years, nanoparticles and mesoporous solid assembly systems have attracted a new interest. A variety of mesoporous composite systems have been designed to explore their photoelectric and sensitive properties. An important characteristic of this system is that it not only has the properties of nanoparticles themselves, but also produces some new effects through the interface of nanoparticles and matrix. The characteristics of the whole system are closely related to the pore size of the matrix, the specific surface and the volume percentage of the small particles. Small particles can be isolated from each other through the pores of the matrix, so that the whole system behaves as nanoparticles. The overall property of the system can be expressed as a three-dimensional block through the connectivity of voids and the seepage effect. In this way, a variety of mesoporous complexes can be assembled according to people’s needs. At present, the system can be divided into inorganic mesoporous and polymer mesoporous complexes according to the types of supports. Small particles can be: metals, semiconductors, oxides, nitrides, carbides. According to the state of the support body, it can be divided into ordered and disordered mesoporous complexes.

2. Synthesis of high-performance nano-structured materials

The emphasis on nano-structured metals and alloys is on greatly improving the strength and hardness of materials, using nano-particles with small sizes

The no-dislocation or low-dislocation density area caused by the effect makes it reach high hardness and strength. The hardness and yield strength of the nanostructured copper or silver bulk materials are 50 times higher than that of conventional materials. Of nano ceramic material, improve the fracture toughness, reduce the brittleness, fracture toughness of silicon carbide nanometer structure 100 times higher than that of conventional materials, n – ZrO2 + Al2O3, n – SiO2, Al2O3 composites, fracture toughness 4 to 5 times higher than that of conventional materials, the reason is that this kind of nano ceramic large volume percentage of interface provides high diffusion channels, diffusion creep significantly improve the brittleness of the interface.

3.Nanometer addition modifies traditional materials

Appeared in this respect is very has the application prospect of new, high Curie temperature, low resistance PTC ceramic material, adding a small amount of nano oxide milling can reduce the sintering temperature, dense speed, decrease the volatilization of Pb, greatly improve the performance of PTC ceramics, scale of 60 nm of zno varistor, nonlinear threshold voltage of 100 v/cm, and 4 mm zinc oxide, the threshold voltage is 4 kv/cm, if you add a small amount of nano materials, can be modulation, the threshold voltage ranging between 100 v ~ 30 kv, New nano-zno varistor with different threshold voltage can be designed according to the needs. Adding 3%-5% 27nm nano-zno into alumina ceramic substrate material can improve the thermal stability by 2-3 times and thermal conductivity by 10%-15%. Nanomaterials are added to plastics to improve their aging resistance and life span. Adding rubber can improve dielectric and wear resistance properties. Nanometer materials can be added to other materials according to the need to select the appropriate materials and the amount of addition to achieve the purpose of material modification, broad application prospects.

4.Design and synthesis of nanometer coating materials

It is nearly 1-2 years nanometer materials science, one of the hot topics in the study of international main research gathered on functional coatings, including traditional materials, fiber coating and coating particles on the surface of the coating, the progress in this respect soon, 80 nm of tin oxide and 40 nm oxide qin, 20 nm chromium trioxide and resin composite can be used as the coating, electrostatic shielding 80 nm of BaTiO3 as high dielectric insulation coating, 40 nm Fe3O4 can be used as a magnetic coating on the 80 nm of Y2O3 can serve as infrared shielding coating, reflective thermal efficiency is high, used for infrared window material. According to the characteristics of nanoparticles in recent years and designed the ultraviolet reflection coating, various kinds of shielding infrared absorption coating, infrared coating and microwave infrared stealth coating, in this research by has a tendency to rise, now in addition to the design need of coating properties, main research focused on the spraying method, most of the research is still stay in the laboratory stage, Japan and the United States on electrostatic shielding coating, insulation coating technology breakthrough, are entering the stage of industrialization production.

5.Surface modification and coating of nanoparticles

This kind of research is mainly aimed at preventing nanoparticles from growing up and solving the agglomeration problem, which has a clear application background. The United States has successfully coated the surface of ZrO2 nanoparticles with Al2O3, the surface of nanometer Al2O3 with ZrO2, the surface of SiO2 with organic coating, and the surface of TiO2 with both organic and inorganic coating have been completed in the laboratory.

The coated particles not only eliminate the electrification effect on the surface of the particles and prevent agglomeration, but also form a potential barrier, which makes it difficult for them to grow up during the synthesis and sintering process. The organic coating enables the inorganic particles to reach the infiltration state with organic matter and organic reagents. This provides a good foundation for the incorporation of inorganic particles into polymer plastics. These basic researches have promoted the development of nanocomposites.

In the United States, small particles of organic material coated with nano-oxide have been successfully added to plastics in the laboratory, increasing the strength and melting point of the material. At the same time, the water resistance is enhanced and the light transmission is improved. The addition of high dielectric nanoparticles can also enhance the insulation of the system. It has a good application prospect in packaging materials.

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