Chemical vapour and sol-gel syntheses of nano-composites and -ceramics using metal-organic precursors

Nano-sized alloy-metal oxide composite and ceramics were prepared using sin gle source alkoxide precursors. The molecule, [Ni2Sn2(OBut)(8)]. has been u sed in a low-pressure CVD process to grow composite thin films where the bi nary alloy Ni3Sn4 is dispersed in a SnO2 matrix. The characterization of th e layers by several analytical methods confirmed the biphasic nature of the obtained material and a homogeneous interdispersion of Ni3Sn4 and SnO2 cry stallites. The mixed-metal alkoxides [BaZr(OH)(OPri)(5)((PrOH)-O-i)(3)](2). [BaTi(OH)(OPri),((PrOH)-O-i)(3)](2) and [Ba2TiZr(OPri)(12)] were used as m olecular precursors for a size-controlled synthesis (Sol-Gel) of the cerami cs BaTiO3. BaZrO3 and BaZr0.5Ti0.5O3. respectively. The complete crystalliz ation of the pervoskite structure is clearly observed at relatively lower t emperature of 600 degreesC for the binary oxides and at 400 degreesC for th e ternary oxide system. Analytical electron microscopy investigations on th e samples revealed a homogeneous stoichiometry on the nanometer level and n arrow crystallite size distributions. (C) 2001 Acta Materialia Inc. Publish ed by Elsevier Science Ltd. All rights reserved.