Preparation of tantalum powders by reduction of complex oxyfluoride compounds by sodium
https://doi.org/10.17073/1997-308X-2015-3-11-17
Abstract
Substances (K2Ta2O3F6, K3TaOF6, K2TaOF3, and KTaOF4) most suitable for the use as oxygen-containing additives in the sodiumthermal fabrication of finely dispersed tantalum powder are selected from the melts containing complex oxyfluoride compounds of tantalum based on thermodynamic and experimental investigations of reduction reactions of tantalum compounds with sodium. The application of mentioned compounds gives the opportunity to fabricate the tantalum powders with the specific surface at a level of 3–5 m2/g, which is higher by a factor of 8–10 compared with powders prepared under the same conditions upon reducing K2TaF7. It is shown that the prepared tantalum powders can be demanded as the initial material to create the capacitor powder with the charge of 70000–100000 μC/g.
About the Authors
V. N. KolosovRussian Federation
M. N. Miroshnichenko
Russian Federation
T. Yu. Prokhorova
Russian Federation
V. M. Orlov
Russian Federation
References
1. Balaji Т., Govindaiah R., Sharma M.K. et al. Sintering and electrical properties of tantalum anodes for capacitor applications. Mater. Lett. 2002. Vol. 56. No. 4. P. 560—563.
2. Purushotham Y., Ravindranath K., Kuma A. Quality improvements in tantalum powder by automation of sodium reduction system. Int. J. Refract. Metal. Hard Mater. 2009. Vol. 27. No. 3. P. 571—576.
3. Mizusaki Y., Iijima H., Noguchi Y. Pat. 7679885 (USA). Tantalum powder and methods of manufacturing same. 2010.
4. Kolosov V.N., Orlov V.M., Miroshnichenko M.N., Prokhorova T.Yu. Preparation of high purity tantalum powders by sodium thermal reduction. Inorganic Materials. 2012. Vol. 48. No. 9. P. 903—907. (In Russ.: Poluchenie vysokochistykh poroshkov tantala natrietermicheskim metodom Neorganicheskie Materialy. 2012. Vol. 48. No. 9. P. 1023—1027).
5. Prokhorova T.Yu., Orlov V.M., Miroshnichenko M.N., Kolosov V.N. Effect of tantalum capacitor powder preparation conditions on the dielectric loss tangent of anodes. Inorganic Materials. 2014. Vol. 50. No. 2. P. 145—149. (In Russ.: Vliyanie uslovii polucheniya tantalovykh kondensatornykh poroshkov na tangens ugla dielektricheskikh poter. Neorganicheskie Materialy. 2014. Vol. 50. No. 2. P. 161—165).
6. Polyakova D.P., Kononova Z.A., Kremenetskii V.G., Polyakov E.G. Vliyanie kisloroda na kompleksoobrazovanie i elektrokhimicheskie protsessy v rasplave [The effect of oxygen on the complexation and electrochemical processes in melt]. Elektrokhimiya. 1997. Vol. 33. No. 9. P. 1088—1097.
7. Chamelot P., Palau P., Massot L. et al. Electrodeposition process of tantalum (V) species in molten f luorides containing oxide ions. Electrochem. Acta. 2002. Vol. 47. P. 3423—3429.
8. Amosov V.M. K termokhimii kompleksnykh galogenidov i oksigalogenidov tantala i niobiya [On the thermochemistry of complex tantalum and niobium halides and oxyhalides]. Izv. Vuzov. Tsvetnaya Metallurgiya. 1964. No. 3. Р. 123—130.
9. Ryabin V.A., Ostroumova M.A., Svit T.F. Termokhimicheskie svoistva veshchestv [Thermodynamic Properties of Substances]. Leningrad: Khimiya, 1977.
10. Masloboeva S.M., Kuznetsov V.Ya., Zalkind O.A. Synthesis and study of potassium peroxypentafluorotantalate monohydrate. Russ. J. Inorgan. Chem. 2009. Vol. 54. No. 1. P. 17—21. (In Russ.: Sintez i issledovanie monogidrata peroksipentaftorotantalata kaliya. Zhurnal Neorganicheskoi Khimii. 2009. Vol. 54. No. 1. P. 20—23.).
11. Kolosov V.N., Orlov V.M., Miroshnichenko M.N., Prokhorova T.Yu. Natrietermicheskoe vosstanovlenie termoobrabotannogo v atmosfere vozdukha geptaftorotantalata kaliya. In: ovye podkhody v khimicheskoi tekhnologii mineral’nogo syr’ya. Primenenie ekstraktsii i sorbtsii: Mater. 2-oi Ross. konf. s mezhdunarodnym uchastiem [Sodium thermal reduction of potassium heptafluorotantalate heat_treated in air atmosphere. In: New approaches in chemical technology minerals. Use of extraction and sorption: Mater. 2nd Russian Conf. ith Int. participation (St. Peterburg)]. Apatity: Kola Scientific Center RAS. 2013. Pt. 2. P. 139—142.
12. Konstantinov V.I. Elektroliticheskoe poluchenie tantala, niobiya i ikh splavov [Electrodeposition of Tantalum, Niobium, and Their Alloys]. Moscow: Metallurgiya, 1977.
13. Lin C., Jiang H., Gong H. et al. Low-temperature synthesis of K2Ta2O3F6. J. Fluor. Chem. 2012. Vol. 144. P. 171—175.
14. Agulyansky A. The chemistry of tantalum and niobium fluoride compounds. Amsterdam: Elsevier, 2004.
15. Orlov V.M., Kolosov V.N., Belyaevskiy A.T. et al. Morfologiya natrietermicheskikh poroshkov tantala i nioibiya v zavisimosti ot sposoba vosstanovleniya [Morphology of odiumreduced tantalum and niobium powders versus a method of reducing]. Pekspektivnye materialy. 2013. No. 4. С. 13—20.
16. Rosenberg L.A., Shtel’man S.V. Sostoyanie kisloroda v tantalovykh poroshkakh [Oxygen species in tantalum powders]. Izvestiya Akademii Nauk SSSR. Metally. 1985. No. 4. Р. 163—164.
Review
For citations:
Kolosov V.N., Miroshnichenko M.N., Prokhorova T.Yu., Orlov V.M. Preparation of tantalum powders by reduction of complex oxyfluoride compounds by sodium. Powder Metallurgy аnd Functional Coatings (Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional'nye Pokrytiya). 2015;(3):11-17. (In Russ.) https://doi.org/10.17073/1997-308X-2015-3-11-17