DIELECTRIC PROPERTY AND EQUIVALENT-CIRCUIT OF ALPHA-ZIRCONIUM PHOSPHATE SYSTEM RELATED TO THE PHASE-TRANSITION AND ITS AFM IMAGE

The surface structure of alpha-ZrP was studied by AFM and the lattice parameters estimated from the image were a = 8.8 Angstrom and b = 5.2 Angstrom. With the TG, DTA and X-ray analyses, the dielectric properti es in the temperature range 15 to 750 degrees C followed Zr(HPO4)(2) . H2O, Zr(HPO4)(2) . 0.37H(2)O, Zr(HPO4)(2) and ZrP2O7 phase transition s as the temperature increased. In addition, the destroying and reform ing processes from one phase to the next phase could be elucidated fro m the dielectric results. The dielectric relaxations induced by the pr otons between the phosphate layers in Zr(HPO4)(2) and by the fluctuati ons of the molecular subgroups when ZrP2O7 is formed appeared at above several kHz in frequency measurement range 20 Hz to 1 MHz. The dielec tric relaxation, impedance and modulus spectra were used to study the electric components contributed to the phases and to find the equivale nt circuits. (C) 1998 Elsevier Science Ltd. All rights reserved.