The Research On The Preparation Of Ni Nano-powders By High-Frequency Thermal Plasma Method

Nanotechnology is a new discipline that is based on modern advanced science and technology, and the size of the materials studied is about100nm or less, with the rapid development of science and technology and modern industry, nano-techno logy has been matured and get wide applications in many areas.Nickel nano-powders, because of with smaller size, so its have higher surface-to-mass ratio, higher chemical activity of the surface atoms and surface energy. There are some unusual physical and chemical properties of nickel nano-powders due to their properties of atoms, and variety of excellent materials can be prepared use these special properties. Although there is a wide range of application of nano-powders in many fields, but the application and development are relatively slow in industry, the main reasons are that the cost of nano-powders preparation, because of the higher production cost, serious agglomeration and oxidation, difficult to collect, etc. These factors limit the application of nano-powders in industry.Among the methods of synthesize nano-powders, physical method is one of the best ways, because of the nano-powder that prepared by physical methods with high purity and rules spherical morphology and well dispersibility, easy to control particle size and morphology, so its were used by many industry and research institutions. But high-frequency thermal plasma method is a relatively better typical physical method due to their high temperatures and energy densities and rapid quenching rate, so it can be prepared nickel nano-powders that using high frequency induction thermal plasma method, and the nano-powders have excellent property in various aspects.High-frequency induction thermal plasma equipment is self-designed and prepared in this paper, and use equipment to synthesize nickle nano-powders, experiments show that the device is running well and can prepare excellent nickel nano-powders, which is compared with other high-frequency thermal plasma devices, the method and device reduces the cost of production, improve the utilization of resources, solve the oxidation and collection of nickel nano-powders, and it can reduce the agglomeration between nano-powders by added to quenching gas in the port of collected device.synthesized particles were analyzed by X-ray diffraction (XRD) and transmis-sion electron microscopy (TEM) and scanning electron microscopy (SEM) to morphology and particle size, composition and crystal structure, and dispersion effect,etc. The results show that its size distribution main ranges from10to120nm, the nickel nano-powders that from different parameters, its average particle diameter distribution ranges from20to65nm and with rules spherical morphology and better dispersibility, its crystal structure is face-centered cubic structure (fcc), but the degree of oxidation is relatively serious.Through theoretical analysis and contrast experimental, the experimental parameters of synthesize nickel nano-powders are ultimately selected, the proper feeding rate was about5g/min, the working gas(or plasma gas) rate is0.5L/min and quenching gas at a rate of2.0L/min, and reduce the agglomeration of nano-powders by introducing passivation treatment.The effect of experimental parameters on the properties of nickle nano-powders was systematically studied in the present research, and the problems during the preparation of nickle nano-powders by high-frequency induction thermal plasma method were solved effectively. The device has many advantages such as lower equipment cost, smaller size of volume, lower energy consumption and without pollution of electrodes,etc. Therefore, the devices and method have wide potential applications.