Synthesis, characterization and thermal expansion of the zinc-containing phosphates with the mineral-like framework structures

Abstract

The new phosphates ZnxMg0.5+xE2−x(PO4)3 (E = Ti, Zr) were synthesized by the sol–gel method followed by heat treatment. Obtained samples were characterized with X-ray, IR, DTA and microprobe electron analyses. The ZnxMg0.5+xTi2−x(PO4)3 solid solution (0 ≤ x ≤ 0.5, kosnarite-type, sp. gr. R$$\bar{3}$$) is stable up to 1323 K. The ZnxMg0.5+xZr2−x(PO4)3 solid solution (0 ≤ x ≤ 0.5, Sc2(WO4)3-type, sp. gr. P21/n) is thermally unstable above 1273 K. The thermal expansion of ZnxMg0.5+xE2−x(PO4)3 solid solutions was studied in the temperature range 298–1073 K. The magnitudes of average volume thermal expansion coefficients vary from 1 × 10−5 to 5 × 10−6 K−1. The composition regulation of these medium- and high-expanding materials allows you to change the characteristics of thermal expansion in the required direction.