초음파 분무 열분해법으로 제조한 텅스텐 미세분말의 미세조직과 소결 거동

• Published in: 대한금속·재료학회지, 59(5) Vol. 59; no. 5; pp. 289 - 294
• Main Authors: 조현희, Hyeonhui Jo, 김정현, Jeong Hyun Kim, 이영인, Young-in Lee, 정영근, Young-keun Jeong, 오승탁, Sung-tag Oh
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 01.05.2021; 대한금속·재료학회
• Subjects: hydrogen reduction; microstructure; spark plasma sintering; tungsten; ultrasonic spray pyrolysis; 재료공학
• ISSN: 1738-8228; 2288-8241
• DOI: 10.3365/KJMM.2021.59.5.289

The powder microstructure and sintering behavior of W prepared by ultrasonic spray pyrolysis and spark plasma sintering were investigated. Fine-grained W powders were synthesized by ultrasonic spray pyrolysis using an ammonium metatungstate hydrate solution and hydrogen reduction. The XRD analysis of the powder, pyrolyzed below 600 ℃, showed tungsten oxide hydrate and WO 3 peaks, while the powder pyrolyzed at 700 ℃ was composed of only the WO 3 phase. As the precursor concentration increased, the particle size of the WO 3 powder increased, which was interpreted to be due to an increase in the amount of solute in the droplet. The hydrogen-reduced powder showed a spherical shape with fine pores inside. XRD and XPS analysis revealed that the WO 3 powder was completely reduced to metallic W by hydrogen reduction, and some oxide layers existed on the powder surface. The consolidated specimen prepared by spark plasma sintering of hydrogen-reduced W powder exhibited a relative density of 94.1% and a Vickers hardness value of 3.89 GPa. The relative density and hardness of the specimens prepared by ultrasonic spray pyrolysis showed relatively lower values than when commercial W powder, with an average particle size of 1.22 μm, was sintered under the same conditions. These results were explained by the formation of agglomerates in the W powder prepared by the ultrasonic spray pyrolysis method. (Received February 23, 2021; Accepted March 15, 2021)