The influence of condition of the monazite structured La0.9Y0.1PO4 nanocrystals sintering on thermal and mechanical properties of the material

A lanthanum orthophosphate- and yttrium-based monazite structured La0.9Y0.1PO4 nanocrystalline material was synthesized. The influence of the thermal treatment temperature on its thermal and mechanical properties has been determined. It was shown that the hydrothermal treatment of coprecipitated phosphates at 230 degrees C for 110 minutes yielded monazite structured nanoparticles with the crystallite size of about 16 nm. Nanopowder thermal treatment for 20 min in the annealing-quenching mode at 1000-1400 degrees C resulted in obtaining compact materials, the porosity of which varied from 52 to 27% with the grain growth from similar to 20 to similar to 100 nm. Active sintering occurred at temperatures above 1300 degrees C. Nanocrystalline materials obtained by heat treatment at 1200 degrees C with a grain size of similar to 40 nm have a porosity of 42%, microhardness of H-v (25 degrees C) = 4 +/- 0.5 GPa, thermal conductivity lambda(25 degrees C) = 0.4 W.m(-1).K-1, and can be used as thermal insulation material.

Automated summary

This study synthesized nanocrystalline La0.9Y0.1PO4 material with monazite structure through thermal treatment, and investigated the influence of treatment temperature on its properties. Annealing-quenching treatment at different temperatures resulted in varied porosity, grain growth, and active sintering above 1300 degrees C. Nanocrystalline materials with a grain size of around 40 nm treated at 1200 degrees C exhibited good thermal and mechanical properties, suitable for thermal insulation applications.