Study of the chemical stability of Sr_0.5Zr₂(PO₄)₃ phosphate with a cosnarite structure in various environments

Abstract

Samples of ceramics based on Sr0.5Zr2(PO4)3 phosphate with the structure of the kosnarite mineral (NaZr2(PO4)3, NZP) were obtained by electric pulse plasma sintering. Submicron phosphate powders with particle sizes less than 1 μm were obtained by the sol-gel method. Powders and ceramics have a single-phase NZP structure. The relative density of the ceramics was 97.6%. The chemical stability of the obtained ceramics was studied in static mode at 90°C in distilled and mineral water and in acidic and alkaline environments. The minimum achieved leaching rates were ~10-4-10-6 g/(cm2 day). The in uence of the contact environment on the rate and mechanism of Sr leaching from Sr0.5Zr2(PO4)3 ceramic samples within 42 days was studied. It has been shown that Sr leaching occurs due to the dissolution of the surface layer of ceramics when tested in distilled water and in mineral water (up to 7 days) and due to Sr leaching from the open ceramic surface after 7 days of testing in mineral water.