Based on the traditional planar flow casting technique, a new metal powder process of modified planar flow casting atomization has been developed. An atomization apparatus was designed and built, with which fine tin-lead solder powder of narrow size distribution and round shape was produced. The whole atomization process is divided into three consecutive stages including the formation of a thin liquid metal ribbon, the disintegration of the molten metal ribbon and the acquisition of metal powder. Corresponding to the three-stage subdivision, a complete mathematical model has been established. The calculated results are in good agreement with the available experimental evidence. The effects of main technological parameters such as mass flow rate, wheel velocity, nozzle geometry, gas density on powder sizes and other calculated variables are considered in detail. The model can be used to optimize operation of the process or to determine its dependence on any of the geometric or physical parameters.
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