Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Synthesis of ${\alpha}$-Alumina Nanoparticles Through Partial Hydrolysis of Aluminum Chloride Vapor

염화알미늄 증기의 부분가수분해를 통한 알파 알루미나 나노입자 제조

  • Park, Hoey Kyung (Department of Chemical Engineering, Kongju National University) ;
  • Yoo, Youn Sug (Department of Chemical Engineering, Kongju National University) ;
  • Park, Kyun Young (Department of Chemical Engineering, Kongju National University) ;
  • Jung, Kyeong Youl (Department of Chemical Engineering, Kongju National University)
  • Published : 2011.10.01
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Abstract

Spherical alumina precursors represented by $AlO_xCl_y(OH)_z$, 30~200 nm in particle diameter, were prepared by partial hydrolysis of $AlCl_3$ vapor in a 500 ml reactor. Investigated on the particle morphology and size were the effects of the reaction time, the stirring speed and the reaction temperature. The particle morphology and size was insensitive to the reaction time in the range 20 to 300 s. The variation of the stirring speed from 0 to 300 and 800 rpm showed that the particle size was the largest at 0 rpm. As the temperature was varied from 180 to 190, 200, $140^{\circ}C$, the particle size showed a maximum at $190^{\circ}C$. By calcination of the as-produced particles at $1,200^{\circ}C$ for 6h with a heating rate of $10^{\circ}C$/min, ${\alpha}$-alumina particles 45 nm in surface area equivalent diameter were obtained. The particle shape after calcination turned wormlike due to sintering between neighboring particles. A rapid calcination at $1400^{\circ}C$ for 0.5 h with a higher heating rate of $50^{\circ}C$/min reduced the sintering considerably. An addition of $SiCl_4$ or TMCTS(2,4,6,8-tetramethylcyclosiloxane) to the $AlCl_3$ reduced the sintering effectively in the calcination step; however, peaks of ${\gamma}$ or mullite phase appeared. An addition of $AlF_3$ to the particles obtained from the hydrolysis resulted in a hexagonal disc shaped alumina particles.

500 mL 교반탱크반응기 내에서 $AlCl_3$ 증기를 $H_2O$ 증기에 의해 부분 가수분해시켜 30~200 nm 크기의 $AlO_xCl_y(OH)_z$로 표시되는 구형의 알루미나 전구체 입자를 제조하였다. 반응시간, 교반속도, 반응온도가 생성된 입자의 형상, 크기 등에 미치는 영향을 조사하였다. 반응시간을 20, 60, 300 s로 변화시킨 결과 생성 입자의 형상 및 크기에 별다른 차이가 없었으며, 교반속도를 0, 300, 800 rpm으로 변화시킨 결과 0 rpm에서 입자의 크기가 최대값을 보였고, 반응온도를 180, 190, 200, $240^{\circ}C$로 변화시킨 결과 $190^{\circ}C$에서 제조된 입자의 크기가 가장 작게 나타났다. 가수분해 생성물 입자를 $10^{\circ}C$/min의 속도로 $1,200^{\circ}C$까지 가열하고 6 시간동안 하소시켜 45 nm 크기의 ${\alpha}$ 알루미나 입자를 얻었다. 하소과정에서 인접입자 사이의 소결에 의해 입자 형상이 구형에서 벌레모양으로 변환되었다. 하소온도를 $1,400^{\circ}C$로, 승온속도를 $50^{\circ}C$/min 로 증가시키고, 유지시간을 0.5 시간으로 감소시켜 급속 하소시킴으로써 인접입자의 소결을 상당히 감소시킬 수 있었다. $AlCl_3$의 가수분해 과정에서 소량의 $SiCl_4$ 또는 TMCTS(2,4,6,8-tetramethylcylosiloxane) 첨가에 의해 인접입자의 소결 방지 효과가 나타났으나, ${\alpha}$ 결정 이외에 ${\gamma}$ 결정, mullite 결정 등이 함께 생성되었다. 하소과정에서 $AlF_3$를 첨가한 결과 육각형 디스크 형상의 ${\alpha}$ 알루미나 입자가 생성되었다.

Keywords

References

  1. Yang, R. J., Yen, F. S., Lin, S. M. and Chen, C. C., "Microstructure-Controlled Effects on Temperature Reduction of $\alpha-Al_{2}O_{3}$ Crystallite Formation," J. Cryst. Growth, 299, 429-435(2007). https://doi.org/10.1016/j.jcrysgro.2006.12.008
  2. Klug, J. and Prochaka, S., "Alumina-Silica Phase Diagram in the Mullite Region," J. Am. Ceram. Soc., 70(10), 750-759(1987). https://doi.org/10.1111/j.1151-2916.1987.tb04875.x
  3. Okuyama, K., Kousaka, Y., Tohge, N., Yamamoto, S., Wu, J. J., Flagan, R. C. and Seinfeld, J. H., "Production of Ultrafine Metal Oxide Aerosol Particles by Thermal Decomposition of Metal Alkoxide Vapors," J. AIChE, 32(12), 2010-2019(1986). https://doi.org/10.1002/aic.690321211
  4. Carbone, T. J., in L. D. Hart(Ed.), Production Processes, Properties, and Applications for Calcined and High Purity Aluminas: Alumina Chemicals, The American Ceramic Society, Inc., 99-108(1990).
  5. Park, Y. K., Tadd, E. H., Zubris, M. and Tannenbaum, R., "Size- Controlled Synthesis of Alumina Nanoparticles from Aluminum Alkoxides," Mater. Res. Bull., 40, 1506-1512(2005). https://doi.org/10.1016/j.materresbull.2005.04.031
  6. Jiang, L., Yubai, P., Changshu, X., Qiming, G. and Jingkun, G., "Low Temperature Synthesis of Ultrafine $\alpha-Al_{2}O_{3}$ Powder by a Simple Aqueous Sol-Gel Process," Ceram. Int., 32, 587-591(2006). https://doi.org/10.1016/j.ceramint.2005.04.015
  7. Tok, A. I. Y., Boey, F. Y. C. and Zhao, X. L., "Novel Synthesis of $Al_{2}O_{3}$ Nano-Particles by Flame Spray Pyrolysis," J. Mater. Process. Technol., 178, 270-273(2006). https://doi.org/10.1016/j.jmatprotec.2006.04.007
  8. Kilian, A. and Morse, T. F., "A Novel Aerosol Combustion Process for the High Rate Formation of Nanoscale Oxide Particles," Aerosol Sci. Technol., 34, 227-235(2001). https://doi.org/10.1080/027868201300034880
  9. Yoo, Y. S., Park, K. Y., Jung, K. Y. and Cho, S. B., "Preparation of $\alpha$-Alumina Nanoparticles via Vapor-Phase Hydrolysis of $AlCl_{3}$, " Mater. Lett., 63, 1844-1846(2009). https://doi.org/10.1016/j.matlet.2009.05.050
  10. Lee, J. W., Yoon, H. S., Chae, U. S., Park, H. J., Hwang, U. Y., Park, H. S., Park, D. R. and Yoo, S. J., "A Comparison of Structural Characterization of Composite Alumina Powder Prepared by Sol-Gel Method According to the Promotes," Korean Chem. Eng., Res.(HWAHAK KONGHAK), 43(4), 503-510(2005).
  11. Park, K. Y. and Jeong, J. K., "Manufacture of Low-Soda Alumina from Clay," Ind. Eng. Chem. Res., 35, 4379-4385(1996). https://doi.org/10.1021/ie950716g
  12. Seo, G. S., Lee, S. G., Ahn, B. H., Ju, C. S., Hong, S. S., Park, S. S. and Lee, G. D., "Effect of Metal Fluoride on the Formation of $\alpha$-Alumina Particles", Korean Chem. Eng. Res.(HWAHAK KONGHAK), 48(5), 627-631(2010).