蒸发凝聚法制备金属超微粉末工艺规律研究

采用自行设计的超微粉末制备装置，在压力为50～1000Pa的Ar气中，利用中频感应加热对坩埚中的金属熔融蒸发，并以水冷螺线管捕获蒸发过程中形成的粉末，研究了蒸发工艺参数对金属蒸发速率、粉末产率和粒度、形貌的影响规律．实验结果表明：采取提高蒸发温度、减小惰性气体压力、加大坩埚直径以及保持金属液面与坩埚口部平齐等措施均能显著地提高金属的蒸发速率和超微粉末产率；在感应加热蒸发法中，粉末和蒸气原子在坩埚口部堆集结壳现象是造成金属难以长时间连续蒸发、金属有效蒸发速率及粉末产率降低的关键原因之一．可以通过加大坩埚直径和保持液面与坩埚口部平齐来克服．

Investigation of the Technological Regularities of Ultrafine Metal Powder Preparation with Evaporation and Condensation Method

The effects of the technological parameters of evaporation on the metal evaporation rate, the yield rate,the mean size and the particle morphologies of powders were investigated with a self-designed ultrafine powder collector, which used induction current as the heating source to evaporate metal copper in crucibleand the water-cooling screwpipe as the capture set in Ar atmosphere. Experiment results showed that higher evaporation temperature, lower inert gas pressure and larger diameter of the heating crucible led to higher evaporation rate of the melt and higher powder yield rate. During the evaporation, the deposited primary particle and vapor atoms on the edge of the crucible prevented the particles and the atoms from flying into the collector, which resulted in low effective evaporation rate and low powder yield rate and made the long-time evaporating procedure difficult. Using a crucible with larger diameter with the height of the melt surface constant was the most effective method to solve these problems.