Ionic Interdiffosion of Functionally Gradient Piezoelectric Materials in PNN/PZT System

The ionic interdiffusions for Nb5+, Ni2+, Zr4+ and Ti4+ ions in the PNN/PZT functionally gradient piezoelectric materials were investigated as a function of diffusion temperature and time respectively. The ionic compositional distribution profiles were examined by electron probe microbeam analysis (EPMA), from which the thickness of the interdiffusion layers were determined.Based on a diffusion model of the overlapped diffusion solute from thin slub, the numerical simulation of the ionic concentration distributions for Nb5+, Ni2+, Zr4+ and Ti4+ ions was carried out by computer, which was in agreement with the EPMA experimental result. The ionic diffusivities and apparent activation energies were estimated, and discussed.