O.A. Graeve, H. Singh, and A. Clifton, "Synthesis and Consolidation of Zirconia Powders Via a Unique Reverse Micelle Synthesis Process and Spark Plasma Sintering," Ceramic Transactions, 194 (2006) 209-223.  Invited Paper.

Yttria-stabilized zirconia powders were synthesized using a reverse micelle synthesis technique, with zirconium oxychloride, yttrium nitrate, isooctane, and Na-AOT as precursors. Upon synthesis and drying, the powders consisted of loss agglomerates of amorphous material. At a temperature close to 500°C the 3YSZ powders crystallized into the tetragonal structure. Upon additional treatment of the powders, the crystallite size increased to values around 20 nm at the highest temperature, which can be attributed to typical grain growth. However, the particle size of the powders did not change, staying below 250 nm for all temperatures. Washing of the powders is a very significant step for post-processing of powders obtained by reverse micelle synthesis. In this work it was found that the use of ethanol and dry ether did not remove impurities. However, the use of hydrogen peroxide allowed the preparation of powders clean of impurities. Spark plasma sintering of the powders treated at 800°C showed that the particle size (agglomerate size) of the powders determined the final grain size of the compact, which was found to be ~250 nm. However, further experiments will be undertaken with the powders treated at lower temperatures in order to corroborate this result. The final density of the compact was found to be >99%.