Nanopowders of yttrium aluminium garnet Y3Al5O12 (YAG) doped with neodymium ions were obtained by the co-precipitation method from the reaction of aluminium and yttrium nitrate and neodymium oxide with ammonia. After washing and drying the hydroxide precursors were calcined at 500, 700, 800 and 900 °C for 1 hour and at 1000 °C for 3 hours. This product was treated by ball milling in a zirconia vial for 0.5, 1.5 and 10 h in order to achieve smaller nanoparticles. The structure, microstructure, morphology and optical properties were investigated by means of diffractometric, microscopic and spectroscopic techniques. The course of the amorphous-to-crystalline transformation was complete after calcining the powder for 1 hour at 900 °C. In the sample calcined for 3 hours at 1000 °C, the mean size of crystallite microdomains was reduced from 600 Å to 300, 250 and 160 Å after 0.5, 1.5 and 10 h of mechanical treatment respectively. The treated product was found to be contaminated with ZrO2. This contamination, from the vial and hardened ZrO2 balls reaches ca. 30 wt % after 10 h of mechanical treatment but causes only a slight reduction of the neodymium luminescence life-time, thus maintaining significant applicative properties.

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Long chain phosphate esters bearing at least one or two aryl groups have been synthesized and used for the preparation of stable multi-walled carbon nanotube (MWCNT) hybrids. The non-covalent interaction ester/MWCNT has been investigated by several techniques (SEM, UV-vis, ³¹P-NMR, RAMAN). The used phosphate ester derivatives demonstrated the ability to produce an excellent dispersion of MWCNT in CHCl₃. The obtained dispersions showed a great stability from one to at least three weeks in the range of concentration considered. Thermal analysis showed an increase in the decomposition temperature for the hybrids with respect to pristine MWCNT.

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