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综合介绍了脉冲电流通过细金属丝放电(pulsed wire discharge,PWD)制备纳米粉体的方法。讨论了影响纳米粉体,特别是晶粒尺寸的因素,以防止形成亚微米颗粒。因为达到电压峰值的丝的沉积能相当于丝的汽化能,因此,能夠计算出沉积能孀潘┘拥哪芰吭黾樱逖沽档停橹?气体的热扩散率增大,晶粒尺寸变小。在惰性气氛中,釆用PWD工艺,由金属蒸气急冷可制备金属粉体。如果介质气体变为氧气或者氨气,就能制备氧化物、氮化物纳米粒子。要制备双金属合金、双氧化物或氮化物纳米粒子就必需采用双金属丝和不同的介质气体。采用PWD工艺,在有机气体或烟气中,能制备电磁屏蔽和导电浆料和其它用途的钝化纳米粒子。采用丝输送器而实现大量生产纳米粉体的PWD工艺一个实例证明了PWD工艺生产纳米粉体的可行性。
A method for preparing nano-powder by pulse current through pulsed wire discharge (PWD) is introduced. The factors that affect the nanopowders, especially the grain size, are discussed to prevent the formation of submicron particles. Since the deposition of filaments that reach the voltage peak corresponds to the vaporization energy of the filaments, it is possible to calculate the deposition rate at which the deposition rate of the gas increases Large, smaller grain size. In an inert atmosphere, preclude the use of PWD process, the rapid cooling metal vapor metal powder can be prepared. Oxide and nitride nanoparticles can be prepared if the medium gas becomes oxygen or ammonia. It is necessary to use bimetallic wires and different dielectric gases for the production of bimetallic, double oxide or nitride nanoparticles. Using the PWD process, passivating nanoparticles can be prepared for electromagnetic shielding and conductive pastes and other uses in organic gases or fumes. An Example of a PWD Process for Mass Production of Nanoparticles Using a Wire Feeder Proves the feasibility of a PWD process for the production of nanopowders.