SYNTHESIS, PHASE FORMATION AND SOME PROPERTIES OF COMPLEX PHOSPHATES OF d-TRANSITION ELEMENTS OF IV GROUP

Abstract

Crystalline phosphates A_1+xTi_2-xFe_x(PO₄)₃ and B_0.5(1+x)D_2-xFe_x(PO₄)₃ (0 ≤ x ≤ 2; A=Li, Na; B=Ca, Sr, Ba; D=Ti, Zr,Hf) were synthesized by solid-state reactions, sol-gel and combined methods. Concentration and temperature regions of phase formation of phosphates of NZP structure were examined. Heat capacity of NaD₂(PO₄)₃ (D=Ti,Zr) in the =range 7-650 K and heat conductivity of NaZr₂(PO₄)₃ and CaTiFe(PO₄)₃ in the range 298-673 K were studied. Obtained results were summarized with literature data on thermophysical and other properties of NZP phosphates.