• 제목/요약/키워드: Tantalum powder

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탄탈륨 산화물의 마그네슘 가스환원에 의한 탄탈륨 금속분말 제조 (Fabrication of Metallic Tantalum Powder by Magnesium-gas Reduction of Tantalum Oxide)

  • 이동원
    • 한국분말재료학회지
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    • 제25권5호
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    • pp.390-394
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    • 2018
  • Metallic tantalum powder is manufactured by reducing tantalum oxide ($Ta_2O_5$) with magnesium gas at 1,073-1,223 K in a reactor under argon gas. The high thermodynamic stability of magnesium oxide makes the reduction reaction from tantalum oxide into tantalum powder possible. The microstructure after the reduction reaction has the form of a mixture of tantalum and magnesium oxide, and the latter could be entirely eliminated by dissolving in weak hydrochloric acid. The powder size in SEM microstructure for the tantalum powder increases after acid leaching in the range of 50-300 nm, and its internal crystallite sizes are observed to be 11.5 to 24.7 nm with increasing reduction temperatures. Moreover, the optimized reduction temperature is found to be 1,173 K as the minimum oxygen concentration is approximately 1.3 wt.%.

수소화-탈수소화법을 이용한 탄탈륨 스크랩으로부터 탄탈륨 분말 제조 연구 (Study on Manufacture of Tantalum Powder from Tantalum Scrap using Hydride-Dehydride Process (HDH Process))

  • 이지은;이찬기;박지환;윤진호
    • 자원리싸이클링
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    • 제27권5호
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    • pp.30-37
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    • 2018
  • 국내 발생하는 고순도 탄탈륨 스크랩을 재활용하기 위해 수소화-탈수소화법(HDH법)에 의한 탄탈륨 분말 제조 연구를 실시하였다. 탄탈륨은 연성 및 강도가 우수하며 융점 또한 높아 분말 제조가 어려운 금속으로 알려져 있다. 따라서 본 연구에서는 수소화를 통해 생성된 탄탈륨 수소화물을 이용하여 탄탈륨 분말을 제조하였다. $500^{\circ}C$, 5시간/$700^{\circ}C$, 3시간 수소화 조건에서 탄탈륨 수소화물이 생성되었고, 탄탈륨 내의 수소는 격자의 팽창 및 전위의 결함으로 작용하므로 탄탈륨 수소화물 분말을 제조하기에 용이하였다. Ring mill을 이용하여 1300 rpm, 30분 이상의 조건에서 $10{\mu}m$ 이하의 크기로 분쇄하였으며, 알곤 및 저진공 분위기에서 탈수소화 공정을 통해 수소 50 ppm 이하의 탄탈륨 분말을 제조하였다.

탄탈륨 분말제조시 분말특성에 미치는 환원제의 영향 (Effect of a Reductant on Production and Characteristics of Tantalum Powder)

  • 윤재식;박형호;배인성;이상백;윤동주;김병일
    • 한국재료학회지
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    • 제11권12호
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    • pp.1047-1051
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    • 2001
  • Purity tantalum powder has been produced by sodium reduction of potassium tantalum fluoride($K_2TaF_7$)in a stainless steel bomb. The influence of experimental variable, such as excess of reductant and temperature of reduction on the yield and quality of the Ta powder has been studied. The excesses of reductant were varied from -20%, -10%, 0%, 5%, 10%, 20%. When -20% excess of sodium was used, the un-reacted sodium remained in the reacted product. The yield of 81% of Ta powder has been achieved by reducing 50g of$K_TaF_7$with 5% sodium in excess of stoichiometric amount in presence of 16.8g of sodium chloride in the charge at a reduction temperature of$905{\circ}C$. The proportion of fine fraction(~325mesh) decreased appreciably with the increase of sodium excess, and the yield of tantalum powder improved from 65% to 94%. The average particle size of Ta Powder is improved from 3 microns to 4 microns in the 5% excess sodium.

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도전체 매개반응(EMR)법에 의한 미세 Ta 분말 제조 (Production of Fine Tantalum Powder by Electronically Mediated Reaction (EMR))

  • 박일;이철로;이오연
    • 한국재료학회지
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    • 제14권10호
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    • pp.719-724
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    • 2004
  • Production of fine tantalum powder by calciothermic reduction of tantalum oxides ($Ta_{2}O_5$) pellet through an electronically mediated reaction (EMR) has been investigated. $Ta_{2}O_5$ pellet feed and reductant calcium-nickel (Ca-Ni) alloy were charged into electronically isolated locations in a molten $CaCl_2$ bath. The current flow through an external path between the feed (cathode) and reductant (anode) locations was monitored. The current approximately 4.7A was measured during the reaction in the external circuit connecting cathode and anode location. Tantalum powder with approximately 99 $mass\%$ purity was readily obtained after each experiment. Tantalum powder by EMR using $Ta_{2}O_5$ pellet feed was fine compared with that of metal powder by metallothermic reduction and EMR using $Ta_{2}O_5$ powder feed.

MR법 및 EMR법에 의한 탄탈륨 분말 제조 (The Production of Tantalum Powder by MR and EMR Method)

  • 배인성;박형호;김병일
    • 열처리공학회지
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    • 제15권1호
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    • pp.16-20
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    • 2002
  • In conventional metallothermic reduction(MR) for obtaining tantalum powder in batch-type operation, it is difficult to control morphology and location of deposits because the reaction occurs by direct physical contact between reductants and feed materials. On the other hand, a electronically mediated reaction(EMR) is capable to overcome these difficulties through the reaction by electron transfer and have a merit of continuous process. In this study an MR and EMR method has been applied to the production of a tantalum powder by sodium reduction of $K_2TaF_7$. As the reduction temperature increases, the particle size and yield of tantalum powder obtained by MR and EMR method is increased.

탄탈륨 및 탄탈륨-텅스텐 합금 분말의 소결성 및 미세조직 연구 (Sintering Behavior and Microstructures of Tantalum and Tantalum-Tungsten Alloys Powders)

  • 김영무;양성호;이성;이성호;노준웅
    • 한국분말재료학회지
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    • 제27권5호
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    • pp.373-380
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    • 2020
  • The purpose of this study is to investigate the densification behavior and the corresponding microstructural evolution of tantalum and tantalum-tungsten alloy powders for explosively formed liners. The inherent inhomogeneous microstructures of tantalum manufactured by an ingot metallurgy might degrade the capability of the warhead. Therefore, to overcome such drawbacks, powder metallurgy was incorporated into the near-net shape process in this study. Spark plasma-sintered tantalum and its alloys with finer particle sizes exhibited higher densities and lower grain sizes. However, they were contaminated from the graphite mold during sintering. Higher compaction pressures in die and isostatic compaction techniques also enhanced the sinterability of the tantalum powders; however, a full densification could not be achieved. On the other hand, the powders exhibited full densification after being subjected to hot isostatic pressing over two times. Consequently, it was found that the hot isostatic-pressed tantalum might exhibit a lower grain size and a higher density as compared to those obtained in previous studies.

콘덴서용 다공성 Ta 분말의 제조 및 특성 (The Properties and Manufacture of Porous Tantalum Powder for Capacitor)

  • 이상일;이승영;원창환
    • 대한금속재료학회지
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    • 제48권4호
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    • pp.326-334
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    • 2010
  • Porous and net-shaped tantalum powder for a capacitor was formulated in a SHS (self-propagating high-temperature synthesis) process. However, this powder, which has weak strength among its particles and low flow ability, cannot be used for a capacitor. Therefore, this powder was sintered in a high-vacuum furnace to increase agglomeration to improve the flow ability, bonding strength among the particles, and shrinkage during pellet sintering. Finally, it was deoxidated with 2 wt% Mg powder to remove the increased surface oxygen that arose during the sintering process. The final product was analyzed in terms of its chemical and physical properties and was compared with a commercial powder used by a capacitor manufacturer.

MR 및 EMR제조공정에 따른 탄탈륨분말 특성 (Characteristics of Tantalum Powder Manufactured by the MR and EMR Process)

  • 박형호;윤재식;배인성;김양수;윤동주;원대희;김병일
    • 한국분말재료학회지
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    • 제14권3호
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    • pp.173-179
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    • 2007
  • In the metallothermic reduction (MR) process used to obtain tantalum powder in one batch, it is difficult to control the morphology and location of the tantalum deposits. On the other hand, an electronically mediated reaction (EMR) process is capable of overcoming this difficulty. The effect of using $K_2TaF_7$ as the raw material and sodium as the reducting agent on the characteristics of tantalum powder are investigated. As the temperature of the reduction varied from 1023K to 1223K, the powder particles obtained with MR were relatively large $({\sim}34{\mu}m)$, while those prepared via EMR were of uniform $(13{\mu}m)$. In the MR process, the Ta powder recovery rate increased from 37% to 83% at 1123K in constrat with EMR process.

산소결핍 탄탈륨 산화물을 활용한 탄탈륨 산질화물 및 질화물 합성 (Synthesis of Tantalum Oxy-nitride and Nitride using Oxygen Dificiency Tantalum Oxides)

  • 박종철;피재환;김유진;최의석
    • 한국분말재료학회지
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    • 제15권6호
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    • pp.489-495
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    • 2008
  • Colored tantalum oxy-nitride (TaON) and tantalum nitride ($Ta_{3}N_{5}$) were synthesized by ammonolysis. Oxygen deficient tantalum oxides ($TaO_{1.7}$) were produced by a titration process, using a tantalum chloride ($TaCl_5$) precursor. The stirring speed and the amount of $NH_{4}OH$ were important factors for controling the crystallinity of tantalum oxides. The high crystallinity of tantalum oxides improved the degree of nitridation which was related to the color value. Synthesized powders were characterized by XRD, SEM, TEM and Colorimeter.

희석제량에 따른 탄탈륨 분말 특성 및 반응온도의 영향 (Characteristic of Tantalum Powder and Effect of Reaction Temperature on the amount of Diluent)

  • 윤재식;박형호;배인성;정성만;김병일
    • 한국분말재료학회지
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    • 제9권5호
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    • pp.315-321
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    • 2002
  • Pure tantalum powder has been produced by combining Na as a reducing agent, $K_2TaF_{7}$ as feed material, KCl and KF as a diluent in a stainless steel(SUS) bomb, using the method of metallothermic reduction. The present study investigated the effect of the amount of the diluent and reaction temperature on the characteristics of tantalum powder in the production process. The temperature applied in this study $850^{\circ}C$ and the amount of the additional reductant from +5% of the theoretical amount used for the reduction of the entire $K_2TaF_{7}$. The results showed that as the amount of the diluent increased, the reaction temperature became lower because the diluent prevented a temperature rise. Also, according to the mixture ratio of the feed materials and the diluent changed from 1 : 0.25 to 1 : 2, the particle size decreased from $5\mutextrm{m}$ to $1\mutextrm{m}$ and a particle size distribution which is below 325 mesh in fined powder increases from 71% to 83%. The average size of Tantalum powder, $2-4\mutextrm{m}$, was close to that of the commercial powders($2-5\mutextrm{m}$). Also under this condition, impurities contained in the powder were within the range allowed for the commercial Ta powders.