Research On The Preparation Technologies And Equipment Of Nanopowders Of Metal

The electric arc and the electric explosion legal system for nanopowder ofmetal mainly for metals, alloys and compounds nanometer micro production, itsproducts as high catalyst, combustion-supporting dose, conductive materials,activated sintering additives, high-performance magnetic materials, such asmagnetic fluid may be widely applied in the military industry, aerospace, powdermetallurgy, oil processing, electronics, machinery, metal frame material tools,Specialist engineering and environmental fields.The each output as electric arc law of nanopowder of metal productiveequipment is 1.5~2.0kg while the average size is 25~60nm and the purity is99.9%.The each output as electric explosion law of nanopowder of metalproductive equipment is 2.0~2.4kg while the average size is 20~50nm and thepurity is 99.9%. These indicators precede others of domestic productionequipment indicators. The method of electric arc has low equipment costs, simpleoperation, micro granularity size Controllable, granularity spread narrow andmany other advantages;Although the method of electric explosion costs higherthan those of former, it may produce sodium, magnesium reactive metalnanometer powder, size distribution narrower and small size micro granularity.Therefore, through this process for both equipment and improvements toproduction will reach international advanced level, also to adapt to user needs andmeet the needs of the market.Main contents this text study as follows:1. Basic theory on the methods of electric arc and electric explosionBefore technological research on electric arc equipment, in order to design areasonable response room, collection storage, on the basis of theory and electricarc electric arc protection in the various characteristics of gas-depth investigationand to supply voltage, current, air-compressors, vacuum pumps provide atheoretical basis for the selection. At the same time to call the explosion theoryalso conducted in-depth research to devise effective large current pulse power,and provide a theoretical basis for the entire circuit.2. The equipment designing for the method of electric arc to preparenanopowder of metal and improving of its productive technologyAiming at raw materials for metal unit of electricity generated energy to theabsorption rate is lower and electrode meltdown reduce the purity metalnanometer powder, crucible is designed to double, with the cooling water andelectrical power system improved.Through improved production equipment chiller breeze to install to the mainbody of producing metal nanometer particles in the appropriate wind-driven, thetimely departure of the main body into cooling devices, to avoid metal nanometerparticles in the thermal heat generated by the district two, three or more timesreunion, thereby produced nanopowder of metal is narrow size distribution belt.using a multi-level high-pressure pumps polyether alternative filtration devicesfor nanometer micro classification.3. The equipment designing for the method of electric explosion to preparenanopowder of metal and improving of its productive technologyThe paper discusses electric explosion method nanometer powder productionequipment motor control technology, in the principles and control system forin-depth study on the basis of the transformation and upgrading of existingtechnologies made to better meet the needs of production.High power is the most critical technologies to electric explosion nanometerpowder production equipment. The original system using the silicon-controlledrectifier-capacitor charge process, often silicon-controlled rectifier was puncture,transformers heated, work capacitor was burned;Such phenomena lead thenormal production equipment to fail. Here a direct current, reverse changeableand the voltage rising thing is set up, using computer-controlled frequencyconversion, adjusting voltage and adjusting voltage speed automatic controlsystem, through frequency, waveform, voltage adjustment to control the size andshape of metal nanometer powder. The process is changing the 380 volts for thecommutation to a direct current frequency via relying devices into HF alternatingcurrent by HF transformers,at last the current are boosted two times to themaximum 60,000 volts.4. The symptom research on nanopowder of metalFirst, introducing the research means of modern symptom technology and itsprinciple , secondly, classifying for the way of symptom , carrying out the natureresearch of nanometer powder on three different levels. To better represent thenature of the metal nanometer career, to the rule of law here in electric arc Ninanometer powder and the electric blasting legal Fe-Co alloy nanometer powderare took out for the clinical research. The final results showed that the legalsystem for electric arc metal nanometer powder relatively mature technology, butin the metal cover crystallization process is varying degrees of unity, leading tothe formation of the chain shape connecting 500-700nm. Through clinicalresearch results, we can change the response of the pressure rooms, increasing thedensity of the gas to increase the speed of metal crystallization, Also we canregulate cooling water temperature, and other parameters to improve the currentquality of nanometer powder. Electric blasting method can produce relativelysmaller size and higher purity metal nanometer powder. TEM analysis shows thatthe particle size distribution of nanometer powder is smaller, the mainconcentration of particles in the 30-50nm, the charging time through regulation,and change the size of discharge energy to produce particle sizes in different areasof nanometer powder.Comprehensive research contents described above,The main contents andconclusions of the research as follows:1. Expounding the research and applications on the theory of the methods ofelectric arc and electric explosion, resulting in a reasonable and effectivetheoretical basis of response room equipment and the design of the explosioncircuit, at the same time finding a good method to improve the equipment andprocesses.2. Completing the design of electric arc response equipment room, cooling, thecollection device.And making comprehensive exposition of the principles based on the factors setaround the response to the legal system for electric arc, and made in-depth studies,in order to further enhance the industrialization of production provide the basis.3. The explosive power circuit is designed. In addition to the original system ispurely mechanical pumps used to send silk body, with hands get round to silk,efficiency is low and it is difficult to accurately control. Automatically intoelectrical current used to, disposals machine control trip from control under thespeed detection devices to send silk feedback control to silk body to preciseaccuracy to 0.001mm.4. Symptom analysis to electric arc and electric explosion legal system of Ni andFe-Co nanometer powder. To further enhance the quality of the production is anadequate basis.