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| Preparation and properties of spherical tungsten powders by plasma rotating electrode process for additive manufacturing |
| LI Xiaohui，CHEN Binke，FENG Zhihua，YANG Xingbo |
| Xi’an Sailong Metal Materials Co.，Ltd，Xi’an 710016，China |
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Abstract The melting point of tungsten and its alloys is as high as 3 410 ℃, and it has the characteristics of high
temperature strength, good heat and corrosion resistance, etc., and is widely used in aerospace, military, nuclear
power and other fields. These characteristics also make tungsten products difficult to process during forming and
post-processing, especially in the deep processing process; and the price of tungsten is also high, so the utilization
rate of raw materials is also particularly important. Metal 3D printing technology is known as one of the key technologies
leading the "third industrial revolution". Compared with traditional processing technology, it has extremely
high material utilization rate. It is especially suitable for free design of complex structures and integrated forming
of complex parts, it is an important supplement to traditional tungsten processing technology. Metal 3D printing
is the main research direction of advanced manufacturing technology. Metal powder, as its most important raw
material, directly affects the performance of printed products. The spherical tungsten powder was prepared by plasma
rotary electrode atomization technology, and the particle size distribution, oxygen content, micromorphism and
surface tissue of tungsten powder were characterized by laser particle size analyzer, O-N analyzer, scanning electron
microscope (SEM). The results show that the spherical tungsten powder particle size is concentrated in a single-
peak distribution of 45~150 μm, the measured average particle size of 80 μm is close to the theoretical average
particle size of 85.5 μm. The oxygen increment of tungsten powder is less than 0.001 5%, and the average oxygen
content of the 45~150 μm powder is 0.000 93%, the oxygen increment is 0.000 38%, and the average oxygen content
of the 15~53 μm powder is 0.002%. The oxygen increase is 0.001 45%. The surface of the 15~53 μm tungsten
powder is smooth and clean, and the surface morphology of the 45~150 μm tungsten powder is relatively small petal-
like cellular dendrites with almost no hollow powder. Tungsten powder has excellent physical properties, fluidityis 6.0~6.2 s/50g, loose density is 11.26~11.35 g/cm3, tap density is 12.4~12.5 g/cm3, and the performance of tungsten
powder with a particle size of 45~150 μm is better than that of 15~53 μm. This research conducted a comprehensive
evaluation of the chemical composition, surface morphology, cross- sectional morphology and physical
properties of spherical tungsten powder prepared by PRPE technology, revealing the advantages of PRPE technology
for preparing high-quality refractory metal powders, and at the same time it helps promote the application of
high-quality refractory metal powders in areas such as additive manufacturing and powder metallurgy.
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Received: 01 February 2021
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2022, Vol. 32 
