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http://dx.doi.org/10.4150/KPMI.2022.29.3.247

Pressureless Sintering and Microstructure of Pure Tungsten Powders Prepared by Ultrasonic Spray Pyrolysis  

Heo, Youn Ji (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
Lee, Eui Seon (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
Oh, Sung-Tag (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
Byun, Jongmin (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
Publication Information
Journal of Powder Materials / v.29, no.3, 2022 , pp. 247-251 More about this Journal
Abstract
This study demonstrates the effect of the compaction pressure on the microstructure and properties of pressureless-sintered W bodies. W powders are synthesized by ultrasonic spray pyrolysis and hydrogen reduction using ammonium metatungstate hydrate as a precursor. Microstructural investigation reveals that a spherical powder in the form of agglomerated nanosized W particles is successfully synthesized. The W powder synthesized by ultrasonic spray pyrolysis exhibits a relative density of approximately 94% regardless of the compaction pressure, whereas the commercial powder exhibits a relative density of 64% under the same sintering conditions. This change in the relative density of the sintered compact can be explained by the difference in the sizes of the raw powder and the densities of the compacted green body. The grain size increases as the compaction pressure increases, and the sintered compact uniaxially pressed to 50 MPa and then isostatically pressed to 300 MPa exhibits a size of 0.71 m. The Vickers hardness of the sintered W exhibits a high value of 4.7 GPa, mainly due to grain refinement.
Keywords
Tungsten; Ultrasonic spray pyrolysis; Cold isostatic press; Microstructure;
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Times Cited By KSCI : 2  (Citation Analysis)
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