Abstract

Nanosized alumina has been synthesized by employing two aluminum salts with monovalent anions that are aluminum nitrate and aluminum chloride as precursors under identical reaction conditions by homogeneous precipitation method. In both the cases, gelation of aluminum hydroxide occurred in comparable pH regime and produced alumina nanoparticles with comparable average particle size, however, their sintering behavior and microstructure of finished products were not comparable. Nanopowders obtained from aluminum nitrate were highly consolidable and sinterable producing reasonable final densities conversely to nanopowders obtained from aluminum chloride which were less consolidable and sinterable, besides the final products showed microstructural flaws including cracks and outgrowths due to inherent passive thermal transformations of nanopowders and unavoidable interferences. DSC/TG, TDA, SEM-EDS, XRD techniques were employed to characterize the nanopowders and dense products.

Keywords:

Aluminum chloride, aluminum nitrate, densification defects, nanoalumina precursors, sintering,

References

1. De Hek, H., R.J. Stol and P.L. De Bruyn, 1978. Hydrolysis-precipitation studies of aluminum (III) solutions. 3. The role of the sulfate ion. J. Colloid Interf. Sci., 64(1): 72-89.
   CrossRef    
2. Matijevic', E., G.E. Janauer and M. Kerker, 1964. Reversal of charge of lyophobic colloids by hydrolyzed metal ions. I. Aluminum nitrate. J. Colloid Sci., 19(4): 333-346.
   CrossRef    
3. Matijevic', E. and L.J. Stryker, 1966. Coagulation and reversal of charge of lyophobic colloids by hydrolyzed metal ions: III. Aluminum sulfate. J. Colloid Interf. Sci., 22(1): 68-77.
   CrossRef    
4. Nagai, H., S. Hokazono and A. Kato, 1991. Synthesis of aluminium hydroxide by a homogeneous Precipitation Method. I. Effect of additives on the morphology of aluminium hydroxide. Brit. Ceram. Trans., 90: 44-48.
   
5. Ramanathan, S., S.K. Roy, R. Bhat, D.D. Upadhaya and A.R. Biswas, 1996. Preparation and characterisation of boehmite precursor and sinterable alumina powder from aqueous aluminium chloride-urea reaction. J. Alloy. Compd., 243(1-2): 39-44.
   CrossRef    
6. Sato, T., S. Ikoma and F. Ozawa, 1980. Preparation of gelatinous aluminium hydroxide by urea from aqueous solutions containing chloride, nitrate and sulphate of aluminium. J. Chem. Technol. Biot., 30(1): 225-232.
   CrossRef    
7. Shackelford, J.F. and R.H. Doremus, 2008. Ceramic and Glass Materials: Structure, Properties and Processing. Springer, New York.
   CrossRef    
8. Shaheen, F., W.A. Shah, M.L. Mirza and M.P. Iqbal, 2005. Effect of concentration of Al2(SO4)3 on the synthesis of Nanosized Alumina. J. Chem. Soc. Pak., 27(6): 602-605.
   
9. Shaheen, F., W.A. Shah, P.I. Qazi and M.L. Mirza, 2006. Development of nanoparticles of alumina by sol-gel method using inorganic Aluminum salts as precursors. Pak. J. Sci. Ind. Res., 49(2): 77-81.
   
10. Stol, R.J., A.K. Van Helden and P.L. De Bryun, 1976. Hydrolysis-precipitation studies of aluminum (III) solutions. 2. A kinetic study and model. J. Colloid Interf. Sci., 57(1): 115-131.
    CrossRef    
11. Unuma, H., S. Kato, T. Ota and M. Takahashi, 1998. Homogeneous precipitation of alumina precursors via enzymatic decomposition of urea. Adv. Powder Technol., 9(2): 181-190.
    CrossRef    
12. Vermeulen, A.C., J.W. Geus, R.J. Stol and P.L. De Bryun, 1975. Hydrolysis-precipitation studies of aluminum (III) solutions. I. Titration of acidified aluminum nitrate solutions. J. Colloid Interf. Sci., 51(3): 449-458.
    CrossRef    

Competing interests

The authors have no competing interests.

Open Access Policy

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Copyright

The authors have no competing interests.