Preparation of PMN–PT–BT/Ag nanocomposites by surface modification with MgO sol

Nanocomposites of 0.96(0.91Pb(Mg1/3Nb2/3)O3–0.09PbTiO3)–0.04BaTiO3 (PBT) with Ag were prepared via synthesis of low-temperature-sinterable PBT/Ag composite powder and its surface modification with a MgO sol. Dielectric properties and modulus of rupture were investigated as a function of the amount of the MgO sol at sintering temperature in the range from 850 to 1000 °C. The MgO sol seemed to suppress the diffusion and migration of Ag during the heat treatment to give rise to the homogeneous microstructure with 300–80 nm of Ag particles in about 3.5–2.5 μm grains. The proper amount of the MgO sol seemed to be 0.5–1.0 wt.% for the PBT powder with 3.0 mol% Ag. The PBT/Ag nanocomposites showed density >99% T.D., ɛrt of 18,000–20,000, tan δ of 1–0.5%, specific resistivity of 1012 Ω cm, and MOR of 125–145 MPa.