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The 1.5‐ to 3‐mol%‐Y2O3‐stabilized tetragonal ZrO2 (Y‐TZP) and Al2O3/Y‐TZP nanocomposite ceramics with 1 to 5 wt% of alumina were produced by a colloidal technique and low‐temperature sintering. The influence of the ceramic processing conditions, resulting density, microstructure, and the alumina content on the hardness and toughness were determined. The densification of the zirconia (Y‐TZP) ceramic at low temperatures was possible only when a highly uniform packing of the nanoaggregates was achieved in the green compacts. The bulk nanostructured 3‐mol%‐yttria‐stabilized zirconia ceramic with an average grain size of 112 nm was shown to reach a hardness of 12.2 GPa and a fracture toughness of 9.3 MPa·m1/2. The addition of alumina allowed the sintering process to be intensified. A nanograined bulk alumina/zirconia composite ceramic with an average grain size of 94 nm was obtained, and the hardness increased to 16.2 GPa. Nanograined tetragonal zirconia ceramics with a reduced yttria‐stabilizer content were shown to reach fracture toughnesses between 12.6–14.8 MPa·m1/2 (2Y‐TZP) and 11.9–13.9 MPa·m1/2 (1.5Y‐TZP).

Three dierent methods of synthesis of ceriagadolinia (CGO) nanopowders are presented. We established a technique of the synthesis of uniformly aggregated, agglomeratefree CGO in which ceriagadolinia composite nanoaggregates (1540 nm) are prepared by nucleation and crystallization of ceria on the surface of preliminary synthesized, hydrolyzed and ultrasonically deagglomerated gadolinia (317 nm). Nanosize aggregates (1265 nm) of CGO were produced during subsequent nonisothermal calcination. The incorporation of the small con centrations of gadolinia in the ceria lattice was studied using the electron spin resonance technique. It was con rmed that Gd 3{ occupies the sites of both cubic and axial symmetry. With increasing concentration, Gd 3{forms a defect complex with the oxygen vacancy.

The 0.75 to 3.0 mol% Y 2 O 3 -stabilized tetragonal ZrO 2 (Y-TZP) and Al 2 O 3 /Y-TZP fine-grained ceramics with 0.2 to 0.7 mass% of alumina were produced by a colloidal technique and low-temperature sintering. Trace alumina addition enhanced the densification of Y-TZP. The influence of the resulting density, microstructure, the yttria-stabilizer and the alumina content on the hardness and toughness were studied. The bulk 2.7Y-TZP ceramic with an average grain size of 110 nm reached a hardness of 13.6 GPa and fracture toughness of 11.2 MPaÁm 1=2 . Y-TZP ceramics with a reduced yttria-stabilizer content were found to reach a fracture toughness of 13.

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CeCl 3 . 7H 2 O and GdCl 3 . 6H 2 O that were dissolved in water were precipitated with urea (NH 2 CONH 2 ) to produce matrix agglomerates for three-component nano-reactors. Mixing hexamethylenetetramine with dilute nitric acid resulted in the formation of well-dispersed nano-particles of cyclotrimetilene trinitramine (C 3 H 6 N 6 O 6 ) (RDX) in the solvent. Nano-reactors were produced by impregnating the nano-C 3 H 6 N 6 O 6 into the matrix agglomerates of an intermediate complex of cerium and gadolinium compounds. Blast initiation of the C 3 H 6 N 6 O 6 resulted in extremely rapid detonation and gaseous products formation at temperatures of 20001-50001C, which were compressed into a volume nearly equal to the initial volume of each RDX nano-particle. Multiple ''nano-blasts'' occurred in the volume of each nano-reactor. The impact of the blast waves led to fragmentation of the surrounding matter. The evolution of a large volume of gaseous products dissipated the heat of the process and limited temperature increase, thus reducing the possibility of local sintering among the primary particles. The shortterm high temperature generated during the blasts enhanced the solid solubility of the metal oxides. Uniform aggregates of 22B74 nm consisting of 6B14 nm crystallites of gadolinia in ceria solid solution were synthesized.

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