Grain refinement is one of the most effective methods to improve the intensity of metals. The method of strengthening metal-alloy-matrix material by adding nano ceramics means spreading powders of nano ceramics to alloy evenly to accelerate the nucleation of alloy and meanwhile restrict the growth of grain and expansion of microcracks in order to refine the grain and improve intensity of product. For example, by adding powders of silicon carbide nanopowder, silicon nitride nanopowder, titanium nitride nanoparticle and silicon nanoparticle to metal matrix (aluminium, copper, silver, steel and ferroalloy), we can make the new-type metal material of light weight, high intensity and excellent heat resistance.
1. Silicon Carbide nanopowder can be used as reinforcing phase for silver alloy.
By adding symmetrical, tiny and well-stable grains to matrix, we can achieve the goal of dispersion strengthening alloy, which is one of the important approaches to prepare high-intensity and high-conductivity alloy material. Silicon Carbide nanoparticles is a kind of effective reinforcing phase for silver alloy. When the content of silicon carbide nanopowder reachs 1% of total mass, the strengthening effect will be the best, tensile strength can reach to 391MPa, relative conductivity will be 60.2% and intensity and abrasion resistance will be improved.
2. Silicon carbide nanopowder can be use to strengthen copper compound material
The copper matrix compound material of high-intensity and high-conductivity has been widely applied to electronic parts and equipments, such as lead-frame of integrated circuit, various kinds of spot welding, electrodes of seam welder, contact material, armature, phase switcher of electric tool and so on. But, the high-intensity and high-conductivity of copper alloy is always a pair of contradictory property. In usual cases, mechanical properties are improved at the cost of conductivity and thermal conductivity to gain high-intensity. The stable silicon carbide nanopowder dispersion strengthened copper matrix material is a good solution to this problem. By adding even, tiny and well-stable silicon carbide nanoparticles to matrix, we can achieve the goal of reinforcing copper alloy and this approach has become the hotspot in the research of high-intensity and high-conductivity compound materials.
3. Application of silicon carbide nanopowder in rubber tyre
By adding certain proportion of silicon carbide nanoparticles to rubber tyre, we can improve the abrasion resistance of tyre by 15%~30% without making any change to original rubber formula or lowering down original performance or quality. Besides, silicon carbide nanopowders can also be applied to other rubber products with requirements of abrasion-resistance, heat-dissipation and heat-resistance, i.e. rubber roller, fuser film sleeve for printer and so on.
4. Silicon carbide nanopowder can be used for Engineering plastic & nano magnetic metals
When the content of silicon carbide nanopowders, which is treated by coupling agent, reaches about 10%, it can greatly improve and perfect the performance of special plastic materials, like PI, PEEK, PTFE and so on, and comprehensively improve the abrasion resistance, thermal conductivity, insulation, tensile elasticity, impact resistance and high temperature resistance of materials.
5. Silicon Carbide nanopowders used for Ceramic matrix compound material
Ceramic matrix compound material is prepared by the compound of multiple nano materials with ceramics as matrix. Ceramics matrix includes Silicon Nitride, silicon carbide and so on. These advanced ceramics are advantageous in high temperature resistance, high intensity and rigidity, light weight, corrosion resistance and so on, but the weak point is their high brittleness. Under the function of stress, there will be cracks and even fracture resulting in failure. The compound of nano materials and ceramics matrix is an effective method to improve the tenacity and reliability of ceramics and produce the nano reinforced ceramic compound material with excellent tenacity.
Ceramic matrix compound materials have been applied to or will be applied to tools, sliding components, engineer parts, energy components and so on. For example, the sophisticated ceramic structural components, which are compounded with silicon nitride nanoparticles, can be applied to ball bearing and roller of rolling bearing, sliding bearing, cover, valve and other structural components with requirements for wear resistance, high-temperature resistance and corrosion resistance in metallurgy, chemical industry, machinery, aviation, spaceflight and energy industry.
6. Silicon carbide nanopowder used for Radar and Infrared Stealth Materials
The small size and quantum size effect of nano material keep more and more atoms on the surface during the refinement of metal, metal oxide and some non-meal materials, the number of dangling bonds increases, and polarization of interface is enhanced providing possibility for the application of wave-absorbing material. Multiple scattering and quantum size effect widen the energy gap of atomic polar of nano ion and the width of energy gap is within the scope of microwave (10ˉ2eV~10ˉ5eV), so it may become a new absorbing channel.
Nano ceramic powder is a new type of ceramic infrared absorbing agent, mainly including silicon carbide nanoparticles, silicon nitride nanopowders and so on. Nano ceramic infrared absorbing agent can absorb a large range of wave band and absorption strength is great. The compound of silicon carbide nanoparticles and magnetic nano absorbing agent (i.e. magnetic metal powder) will have its absorption effect improved greatly. Nano nitride absorbing agent mainly includes silicon nitride Si3N4 and Iron nitride FeN nanopowders. Silicon nitride Nanopowder has a large dielectric loss within 100Hz~1MHz, which is caused by interfacial polarization. Iron nitride nanopowder-FeN has very high saturation magnetic induction strength and saturation magnetic flux density making it possible to become an excellent nano radar absorber.
7. Coating Material
The application of nano materials to coating can improve the abrasion resistance, corrosion resistance and oxidative stability. A large amount of researches have proved that the application of silicon carbide nanopowders, Zirconium carbide nanoparticles, Titanium carbide nanopowders, Titanium nitride nanoparticles, Boron carbide nanopowders to the compound coating of metal can give super abrasion resistance and self-lubrication. Its abrasion resistance is 100 times higher than bearing steel, friction coefficient being 0.06~0.1, and meanwhile it is also equipped with high-temperature stability and abrasion resistance. The application of nano technology to the key parts of engineer of liquid rocket can largely lengthen the service life of these parts.