Ceramic powder synthesis zirconia

Historically, stabilized (and partially stabilized) zirconia ceramics were prepared from powders in which the component oxides are mechanically blended prior to forming and sintering. Because solid state diffusion is sluggish, firing temperatures in excess of 1800°C are normally required. Furthermore, the dopant was nonuniformly distributed, leading to inferior electrical properties. Trace impurities in the raw materials can also lead to enhancement of electronic conductivity in certain temperature ranges, which is also undesirable. To overcome these problems, several procedures have been developed to prepare reactive (small particle size) and chemically pure and homogeneous precursor powders for both fully stabilized and partially stabilized material. Two of these are alkoxide synthesis and hydroxide coprecipitation. 

Recent research efforts have been focused on the synthesis of doped, stabilized zirconia powders, especially with nanometer-sized particles. Nanocrystalline stabilized powders are vital for the preparation of nanocrystalline materials, as their properties are fundamentally different from those of conventional powders, due to the extremely small crystalline dimension, superior phase homogeneity and low-temperature sinterabUity that significantly determines the later-stage processing and sintering properties of ceramics. 

Benfer, S., Popp, U., Richter, H., Siewert, C., and Tomandl, G. (2001). Development and characterization of ceramic nanofiltration membranes. Sep. Purif. Technol 22-23 231-237. Vacassy, V., Guizard, C., Thoraval, V., and Cot, L. (1997). Synthesis and characterization of microporous zirconia powders application in nanofilters and nanofiltration characteristics. J Membr. Sci. 132 109-118. 

Muccillo E.N.S., Souza E.C.C., Muccillo R. Synthesis ofreactive neodymia-doped zirconia powders by the sol-gel technique. J. Alloys. Compd. 2002 344 175-178 Nair J., Nair P., Mizukami K., Oosawa Y., Okubo T. Microstructure and phase transformation behavior of doped nanaostructured titania. Mater. Res. Bull. 1999 34 1275-1290 Nan J., Wu J., Deng Y., Nan C.W. Synthesis and thermoelectric properties of (Naa.Cai c)3Co409 ceramics. J. Eur. Ceram. Soc. 2003 23 859-863. 

Microwave-hydrothermal synthesis and hyperfine characterization of praseodymium-doped nanometric zirconia powders. Journal of the American Ceramic Society, 88, 633-8. 

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