Synthesis and Investigation of Na1 – xR0.33xTiO2(PO4)3 (R = Y or La) Phosphates

Abstract

Phosphates Na1 – xR0.33xTi2(PO4)3 (R = Y or La; 0 ≤ х ≤ 1) were synthesized by the Pechini process and characterized by X-ray diffraction, electron microscopy with microprobe analysis, and IR spectroscopy. The systems exhibit isodimorphism to form a series of solid solutions belonging to the NaZr2(PO4)3 (NZP) structural type and crystallizing in space group Rc or RThe Rietveld structural studies confirmed the isomorphic miscibility of sodium and the rare-earth element in the interstices of the NZP structure. The unit cell parameter с in the phosphates studied tends to increase, and the parameter а tends to decrease, in response to rising temperature, which trends are typical of NZP phosphates.