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This paper is concerned with an investigational study of spheroidization of refractory l tungsten powders by radio frequency thermal plasma,with emphasis on the melting,solidification and growth behavior of the tungsten powder particles in spheroidization process.The flight time and melting time of tungsten powder particles in the plasma were estimated,and the growth behavior of the tungsten powder particles was analyzed in detail by investigating the change of the average particle size before and after plasma spheroidization.The morphology and spheroidization rate were analyzed using field emission scanning electron microscopy.The results showed that the flight time and melting time for tungsten powder with radius of 7.8 μm is estimated as 9.3 ms and 2.9 ms,respectively.The change of powder particle size showed that the growth of tungsten powder particles mainly caused by coalescence processes of droplets in the thermal plasma system.The experimental results demonstrated that the spheroidization rate can reach up to 95% at given parameters in this paper.