【摘要】 高频感应热等离子体在粉体球化领域中具有独特优势。介绍了高频感应热等离子体及其在微细球形粉体材料制备中的应用。以一台30kW装置为例,简略介绍了高频热等离子体的球化过程,展示了部分自制的关键设备,其中送粉器可以实现原料粒径在0.05～50μm范围内、加料质量流量在1.00～100g/min范围内的均匀稳定供给。结合钨粉、氧化硅、氧化铝、镍粉等几种典型产品的球化,分析了热等离子体运行参数、载气量、加料质量流量等关键因素对球化过程和产品质量的影响,提出了热等离子体在球化μm级和nm级粉体时对原料的基本要求。球化μm级粉体时,密实原料的球化率>98%,球化后二氧化硅粉体的密度达到理论值的98.2%;球化后钨粉松装密度增加了19.56%,流动性提高至球化前的2倍以上。球化nm级粉体时可以采用μm级原料,疏松的原料粉体更便于球化,在20～100nm范围内的产品粒径可以通过改变冷却气体积流量进行调控。此外,针对运行成本较高的问题,提出了开发高附加值产品和有效降低热等离子体运行成本是未来发展的主要方向。更多还原

【Abstract】 Radio-frequency induction thermal plasma(RFITP) has a unique advantage in powder spheroidization.Therefore,we demonstrated RFITP and its application in fine spherical powder material preparation.The spheroidization process of RFITP was briefly presented taking the test equipment with 30 kW capability as an example and some key equipments was presented.The homemade feeder can supply powder with a diameter range of 0.05~50 μm in a feed rate range of 1.00~100 g/min.Moreover,on the basis of the spheroidization results of tungsten,silica,alumina,and nickel powders,the key factors,such as thermal plasma parameters,flow of carrier gas and feed rate that can affect the spheroidization process and products,were analyzed.Then we proposed some basic requirements of raw materials for producing μm and nm scale products by using thermal plasma.When μm scale powders were spheroidized,the spheroidization rate of dense raw materials was 98%.The density of silica after spheroidization reached 98.2% of theoretical value.The density of tungsten after spheroidization made an increase of 19.56% and the flowability increased to more than 2 times.When nm scale powders were spheroidized,μm scale powders can be used as raw materials and loose raw material powder was more conducive to the spheroidization.The particle size can be controlled in range of 20~100 nm by changing the volume flow rate of cooling gas.Considering the high cost of the plasma technique,we also proposed two main direction of this application: developing high value-added products and reducing the operation cost.更多还原