Mechanism of complex formation by milling a mixture comprising PbO, TiO2, Nb2O5 and Mg(OH)2 was examined. Due to the strong acidity of Nb2O5 and basicity of Mg(OH)2, a typical acid-base reaction takes place during milling with simultaneous partial reduction of Nb5+ to Nb2+, as evidenced by XPS. This mechanochemical reaction, together with further interaction with PbO and TiO2, brings about precursors of the perovskite solid solution, (1-X)Pb(Mg1/3Nb2/3)O3-xPbTiO3 with x ranging from 0 to 0.2. The mixture after milling is more homogeneous and contains even a small amount of crystalline perovskite. On subsequent heating, growth of perovskite takes place parallel with a solid state reaction via pyrochlore, resulting in a pure perovskite phase at temperatures as low as 850°C. A mixture without mechanical stressing brings about a pyrochlore as a main phase by heating under the same condition.
|ジャーナル||Materials Science Forum|
|出版物ステータス||Published - 1997 12 1|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering