Processing and Sintering of Alumina-YAG Nanocomposites
The elaboration of 50 vol.% Al2O3/YAG (Y3Al5O12) nanocomposites was pursued by comparing two processing routes. In one case, a composite powder was firstly synthesized via reverse-strike co-precipitation and then submitted to an optimized thermal and extensive milling pre-treatment prior to sinter. In the second case, a pure-alumina precursor was prepared via reverse-strike precipitation and then doped with an yttrium salt solution; such doping procedure was performed on alumina samples submitted to several thermal and/or mechanical pre-treatments carried out to yield more or less relevant α-phase amounts. The optimization of the thermal/mechanical pre-treatment of the former powder led to a very homogeneous, dense and fine microstructure, made of α-alumina and YAG grains of about 300 nm in size. On the contrary, sintered bodies characterised by a larger mean grain size and a lower homogeneity in microstructure were obtained by using the second starting powder, even if, also in this case, a suitable control of the powder processing can allow a promising improvement of the microstructural features.
P. Palmero and L. Montanaro, "Processing and Sintering of Alumina-YAG Nanocomposites", Advances in Science and Technology, Vol. 45, pp. 1696-1703, 2006