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Agglomerate formation during drying

Published online by Cambridge University Press:  31 January 2011

Alejandro Vertanessian ,
Andrew Allen  and
Merrilea J. Mayo
Alejandro Vertanessian
Affiliation:
Department of Materials Science & Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802
Andrew Allen
Affiliation:
Ceramics Division, National Institute of Standards and Technology, Building 223/Room A163, 100 Bureau Drive, Gaithersburg, Maryland 20899
Merrilea J. Mayo
Affiliation:
Department of Materials Science & Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802
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Abstract

The evolution of agglomerate structure during drying of particles from suspension has been studied for a nanocrystalline Y2O3 (8% mol fraction)-stabilized ZrO2 powder. Agglomerates in drying and dried suspensions were examined at the smallest size scales (1 nm to 1 μm) using ultra-small angle x-ray scattering (USAXS) and at the largest size scales (100 nm to 10 μm) using scanning electron microscopy. The results were correlated with the degree of particle dissolution in each suspension (measured by flame absorption spectroscopy of the suspension filtrate) and the zeta potential of the particles in suspension prior to drying. Results show that large agglomerates readily form across a pH range from 2 to 9. The fact that Y+3 ion dissolution varies by over four orders of magnitude in this range leads to the conclusion that there is little direct correlation between the degree of Y dissolution and agglomeration in this system (Zr ion dissolution was below the detection limit at all pH values studied). The observation of large agglomerates well before the introduction of air-water interfaces into the drying mass likewise leads to the conclusion that capillary forces are not essential to agglomerate formation. Instead, agglomerates appear to form as a direct consequence of increasing suspension concentration. Zeta potential also plays a role. Specifically, there was a notable change in agglomerate morphology as the isoelectric point was approached, at approximately pH 8. Here USAXS shows the particles in suspension to have a layered interior structure, with small primary particles aggregated in sheets to form each blocky particle. This is in contrast to the more rounded agglomerates formed away from the isoelectric point, which appear to be composed of the same primary particles arranged in chainlike structures. USAXS of powders from the dried suspensions confirms that the structures seen after drying are the same as those present in suspension. The two structural morphologies are attributed to diffusion-limited (sheets) versus reaction-limited (chains) aggregation, respectively.

Type
Articles
Information
Journal of Materials Research , Volume 18 , Issue 2 , February 2003 , pp. 495 - 506
Copyright
Copyright © Materials Research Society 2003

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References

REFERENCES

Kwon, S. and Messing, G.L., Nanostruct. Mater. 8, 399 (1997).CrossRefGoogle Scholar
Maskara, A. and Smith, D.M., J. Am. Ceram. Soc. 80, 1715 (1997).CrossRefGoogle Scholar
Patton, T.C., Paint Flow and Pigment Dispersion (John Wiley and Sons, New York, NY, 1979), p. 266.Google Scholar
Scherer, G.W., J. Am. Ceram. Soc. 73, 3 (1990).CrossRefGoogle Scholar
Çiftçioglu, M. and Mayo, M.J., in Superplasticity in Metals, Ceramics, and Intermetallics, edited by Mayo, M.J., Kobayashi, M., and Wadsworth, J. (Mater. Res. Soc. Symp. Proc. 196, Pittsburgh, PA, 1990) pp. 77–86.Google Scholar
Cullity, B.D., Elements of X-Ray Diffraction (Addison-Wesley Publishing Co., Reading, MA, 1967), p. 99.Google Scholar
Long, G.G., Jemian, P.R., Weertman, J.R., Black, D.R., Burdette, H.E., and Spal, R.D., J. Appl. Crystallogr. 24, 30 (1991).CrossRefGoogle Scholar
Long, G.G., Allen, A.J., Ilavsky, J., Jemian, P.R., and Zschack, P., in Synchrotron Radiation Instrumentation: 11th U.S. National Conference, edited by Pianetta, P., Arthur, J., and Brennan, S. (American Institute of Physics Conf. Proc. 521, Melville, NY, 2000), pp. 183–187.Google Scholar
Lake, J.A., Acta Crystallogr. 23, 191 (1967).CrossRefGoogle Scholar
Potton, J.A., Daniell, G.J., and Rainford, B.D., J. Appl. Crystallogr. 21, 663 (1988).CrossRefGoogle Scholar
Porod, G., in Small-Angle X-ray Scattering, edited by Glatter, O., Kratky, O. (Academic Press, London, U.K., 1982), pp. 17–51.Google Scholar
Skoog, Douglas A. and Leary, James J., Principles of Instrumental Analysis, 4th ed. (Harcourt Brace College Publishers, Fort Worth, TX, 1992), p. 223.Google Scholar
Adair, J.H., Krarup, H.G., Venigalla, S., and Tsukada, T., in Aqueous Chemistry and Geochemistry of Oxides, Oxyhydroxides, and Related Materials, edited by Voigt, J.A., Wood, T.E., Bunker, B.C., Casey, W.H., and Crossey, L.J. (Mater. Res. Soc. Symp. Proc. 432, Pittsburgh, PA, 1997), pp. 101–112.Google Scholar
Basu, R.N., Randall, C.A., and Mayo, M.J., J. Am. Ceram. Soc. 84, 33 (2001).CrossRefGoogle Scholar
Vertanessian, A., M.S. Thesis, The Pennsylvania State University, University Park, PA (2001).Google Scholar
Mittal, B., Puri, V.M., and Mancino, C.F., ASAE Meeting Presentation Paper No. 004011 (2000), available at http://www.asae.org.Google Scholar
Mayo, M.J. and Çiftçioglu, M., in Clusters and Cluster-Assembled Materials, edited by Averback, R.S., Nelson, D.L., and Bernholc, J. (Mater. Res. Soc. Symp. Proc. 206, Pittsburgh, PA, 1991), pp. 545–550.Google Scholar
Beaucage, G., J. Appl. Crystalogrl. 29, 134 (1996).CrossRefGoogle Scholar
Ross, S. and Morrison, I.D., Colloidal Systems and Interfaces (John Wiley & Sons, New York, NY, 1988), p. 233.Google Scholar
Akash, and Mayo, M.J., J. Am. Ceram. Soc. 82, 2948 (1999).CrossRefGoogle Scholar
Allen, A. J., J. Appl. Cryst. 24, 624 (1991).CrossRefGoogle Scholar
Hunter, R.J., Foundations of Colloid Science (Oxford University Presss, Oxford, U.K., 1986), pp. 92–94, 440–447.Google Scholar
Stainton, C., Liang, W., and Kendall, K., Eng. Fract. Mech. 61, 83 (1998).CrossRefGoogle Scholar
Franks, G.V., Johnson, S.B., Scales, P.J., Boger, D.V., and Healy, T.W., Langmuir 15, 4411 (1999).CrossRefGoogle Scholar
Reed-Hill, R.E. and Abbaschian, R., Physical Metallurgy Principles, 3rd ed. (PWS-Kent Publishing Company, Boston, MA, 1992), p. 474.Google Scholar