Preparation of NASICON Silico Phosphates of Composition Na1 + xZr2SixP3 – xO12 by Pyrolysis of Solution in Melt

A new method for preparing Na 1 + x Zr 2 Si x P 3 – x O 12 (0 < x < 3) based on pyrolysis of solution containing a mixture of organic components in rosin melt has been proposed. Effect of superstoichiometric amounts of sodium and phosphorus on the phase composition of synthesis products has been proved. It has been found that precursor for the sample of maximal purity of phase composition is prepared at molar ratio Na : Zr : Si : P = (1.15 + x ) : 2 : x : ( y – x ), where y = 3 (1.20 + x )/(1 + x ). Precursor calcination temperature is 1000°C. Different NASICON compositions without crystalline admixtures have been obtained in the range 1.5 ≤ x ≤ 2.12. The prepared samples have been studied by X-ray powder diffraction and scanning electron microscopy. The disclosed method of synthesis is promising for the preparation of NASICON as both bulk materials and thin layer coatings.