Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
권호 표지

A Study On Properties and Thermal Decomposition of W-Co Salt Powders Synthesized by Spray Drying

분무 건조된 W-Co 복합염의 열분해 및 분말 특성에 관한 연구

  • 권대환 (경상대학교 재료공학부 및 항공기부품기술연구센터) ;
  • 안인섭 (경상대학교 재료공학부 및 항공기부품기술연구센터) ;
  • 하국현 (한국기계연구원 재료공정연구부) ;
  • 김병기 (한국기계연구원 재료공정연구부) ;
  • 김유영 (진주산업대학교 기계공학과)
  • Published : 2001.11.01
Download PDF
⟨ Previous Next ⟩

Abstract

Homogeneous spherical W-Co salt powders were made by spray drying of aqueous solution of ammonium $metatungstate(NH_4)_6(H_2W_{12}O_{40}){\cdot}4H_2O,\; AMT)$ and cobalt nitrate $hexahydrate(Co(NO_3)_2{\cdot}6H_2O)$. The thermal decomposition process of spray dried W-Co salt powders was studied by TG, XRD, SEM, TEM and FT-IR. Spray dried W-Co salt powders were calcined for 1 hour in the temperature from$ 350^{\circ}C$ to $800^{\circ}C$ in atmosphere of air. At the temperatures over $600^{\circ}C$, spherical $CoWO_4/WO_3$ composite oxide powders were obtained. The primary particle size of W/Co composite oxide powders increased with increasing thermal decomposition temperature due to the particle growth. The observed crystallite size by TEM was in the range of 60nm and that of $CoWO_4$ calculated by Scherrer's formula at $800^{\circ}C$ was smaller than 55nm. The crystallite site was identified by XRD and TEM.

Keywords

References

  1. H. E. Exner : Inter. Metallurgical Review 24 (1979) 149
  2. 鈴木, 丸善 : 超硬合金 と 撓結硬質材料 (1988) 249
  3. E. Lardner : Powder Metall., 21 (1978) 65
  4. H. E. Exner and J. Gerland : Powder Metall. 13 (1970) 13
  5. E. A. Almond and B. Roebuck : Very-Fine-Grained Hard Metals, R&HM, September (1981) 137
  6. B. K. Kim, G. H. Ha, D.W. Lee G. G. Lee and I. S. Ahn : Advanced Performance Materials 5 (1998) 341 https://doi.org/10.1023/A:1008665301338
  7. L. E. McCandlish, B. H. Kear and B. K. Kim : Nanostructred Mater. 1 (1992) 119 https://doi.org/10.1016/0965-9773(92)90063-4
  8. B. K. Kim, G. H. Ha, G. G. Lee and D. W. Lee : Nanostructured Materials, 9 (1997) 233 https://doi.org/10.1016/S0965-9773(97)00061-5
  9. B. K. Kim, G. H. Ha, G. G. Lee and D. W. Lee : J. Mater. Pro. Tech., 63 (1997) 317 https://doi.org/10.1016/S0924-0136(96)02748-3
  10. L. Gao and B. H. Kear : Nanostructured Materials, 5 (1995) 555 https://doi.org/10.1016/0965-9773(95)00265-G
  11. S. Wahlberg, I. Grenthe and M. Muhammed : Nanostructured Mater., 9 (1997) 105 https://doi.org/10.1016/S0965-9773(97)00029-9
  12. M. Muhammed, I. Grenthe and S. Wahlberg : U. S. Pat. No. 5594929 (1997)
  13. 山本 良治, 鄕谷 淸, 志垣 憲良 : 超硬合金 と 撓結硬質材料 40, 6 (1993) 609
  14. 山本 良治, 山田 正二, 本川 惺, 志垣 憲良 : 超硬合金 と 撓結硬質材料 40, 11 (1993) 1126
  15. R. A. Swalin : Wiley, (1961) 219
  16. D. W. Sproson, G. L. Messing and T. J. Gardner : Ceram. Int., 12 (1986) 3-7 https://doi.org/10.1016/S0272-8842(86)80003-7
  17. D. H. Charlesworth and W. R. Marshall, Jr. : J. Am. Inst Chem. Eng., 6 [1] (1960) 9
  18. B. D. Cullity : Elements of X-ray Diffraction(2nd ed.), Addison-Wesley pub. Co. Inc., New York (1978) 356
  19. N. E. Fouad, A. K. H. Nohman and M. I. Zaki : Thermochim. Acta 343 (2000) 139 https://doi.org/10.1016/S0040-6031(99)00339-1
  20. R. A. Nyquist and R. O. Kagal : Infrared Spectra of Inorganic Compounds, Academic Press, New York, 1971
  21. Thermochim. Acta v.343 N. E. Fouad:A. K. H. Nohman;M. I. Zaki
  22. Infrared Spectra of Inorganic Compounds R. A. Nyquist;R. O. Kagal