(Na 0.5 Bi 0.5 ) 0.94 Ba 0.06 TiO 3 -Bi 12 TiO 20 composite ceramics, which display macroscopic interfaces and have a net macroscopic polarization, were fabricated by an ordinary sintering technique. All the coarse grains were found to have nano-networked surfaces, implying a relatively high content of amorphous phases in this kind of ceramic. Because these interface-related amorphous phases are distributed non-homogeneously throughout the ceramic, we propose that the macroscopic polarization is due to partial alignment of the distorted TiO 6 octahedra and the distorted BiO 5 polyhedra in the amorphous phases.