In-situ fabrication of ceramic/metal nanocomposites by reduction reaction in barium titanate metal oxide systems

Novel ceramic/metal nanocomposites were prepared by in-situ reduction method in BaTiO3/NiO, BaTiO3/WO3 and BaTiO3/MoO3 systems. The fabrication processes and the phase stability of these metal and metal oxides were studied using X-ray diffraction analysis and thermodynamic consideration. For BaTiO3/NiO system, NiO was entirely reduced at 500 degrees C for several hours and dense BaTiO3/Ni nanocomposites were obtained without additional reaction phases. However, it was confirmed that a small amount of Ni2+ was dissolved in the BaTiO3 lattice. In the BaTiO3/WO3 system, in parallel with the reduction of WO3, BaTiO3 reacted with WO3 or WO2 to produce BaWO4. BaTiO3/W composite powder having no reaction products was difficult to fabricate by in-situ reduction process. On the other hand, BaTiO3/W composite could be obtained from BaTiO3 and W powder mixture when sintering below 1200 degrees C. In contrast, the fabrication of BaTiO3/Mo composite was successfully achieved after reducing BpTiO(3)/MoO3 powder mixture at 800 degrees C. (C) 1998 Elsevier Science Limited. All rights reserved.