Nanoreactor engineering and SPS densification of multimetal oxide ceramic nanopowders

The concept of the in situ engineering of nanoreactors has been suggested and realized. Nanoreactors are morphologically homogeneous aggregates of synthesized complex intermediate metastable products. The thermo-activated processes of nucleation-growth of the final compositions were realized within the preliminary localized volume of each single nanoreactor, which provides the heredity of the final structure of the nanosize products. This new approach of multimetal oxide nanosize powder engineering allowed the prevention of the uncontrolled agglomeration and production of ceramic powders (8YSZ, CGO) consisting of ∼45 nm nano-aggregates of ∼7 nm crystallites with a remarkably homogeneous composition and uniform morphology. The advances from the introduction of the nanoblast calcination technique were also demonstrated. Finally, the SPS consolidation of nanosized aggregates of 8YSZ and CGO was analyzed. The 8YSZ ceramic with an average grain size of 90 nm and CGO nanoceramic with an extremely fine grain microstructure were obtained by low-temperature SPS under the ambient pressures of 100–150 MPa. The CGO ceramics with average grain sizes of 73, 32 and 18 nm were obtained by SPS at 1100, 1050 and 1000 °C, respectively.