X-ray analysis of PLZT solid solution formed under hydrothermal conditions

PLZT solid solutions formed under different hydrothermal conditions (130 similar to 220 degrees C, C-KOH = 1 similar to 5 mol/L, Zr/Ti (molar ratio) = 0/10 similar to 10/0, c(La) = 0 similar to 20%, Pb/(Zr + Ti) (molar ratio) = 1.0 similar to 1.7, reaction time 2 h) were investigated by means of XRD, Incorporating La3+ ion into the lattice of PZT solid solution to substitute Pb2+ or Zr4+ and Ti4+ ions was difficult under above hydrothermal conditions, The La3+ could exist in the grain boundary zone or be adsorbed on the surface of PZT particles, and incorporated gradually into the lattice of PZT with further heat-treatment, A-site substitution was easy to occur in the tetragonal phase zone of solid solution to result in shrinkage of the cell volume of solid solution. A-site and B-site substitutions could occur simultaneously in the rhombohedral phase zone to keep the cell volume unchanging essentially, The existence of La was in favour of the formation of solid solution in the tetra-rhomb morphotropic phase boundary zone, The reaction temperature and concentration of mineralizer KOH have a significant effect on the formation and morphology of solid solution products.