Study of the nanoparticle/matrix interactions in Y2O3–SiO2 samples

Two Y2O3–SiO2 nanocomposites with 10 and 30 wt.% yttrium oxide were obtained by a sol–gel method, and characterized by TEM, X-ray diffraction, FTIR, 29Si MAS and CPMAS NMR spectroscopy. It was found that small (2–3 nm) amorphous yttria nanoparticles are homogeneously dispersed in the silica matrix. Their size does not appear to grow with thermal treatment up to 900 °C nor with yttria content. The silica interacts strongly at the interface with yttria nanoparticles through hydrogen bonds, sometime mediated by bridging water molecules, but also via direct Si–O–Y bonds.