Synthesis of the superfine high-entropy zirconate nanopowders by polymerized complex method

Yangjie Han,Honghua Liu,Renwang Yu,Yanhui Chu

doi:10.1007/s40145-021-0522-x

Yangjie Han, Honghua Liu + Show 2 more

Open Access

https://doi.org/10.1007/s40145-021-0522-x

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Abstract

The high-purity and superfine high-entropy zirconate nanopowders, namely (Y0.25La0.25Sm0.25Eu0.25)2Zr2O7 nanopowders, without agglomeration, were successfully synthesized via polymerized complex method at low temperatures for the first time. The results showed that the crystallinity degree, lattice strain, and particle size of the as-synthesized powders were gradually enhanced with the increase of the synthesis temperature from 800 to 1300 °C. The as-synthesized powders involved fluorite phase in the range of 800–1200 °C while they underwent the phase evolution from fluorite to pyrochlore at 1300 °C. It is worth mentioning that the as-synthesized powders at 900 °C are of the highest quality among all the as-synthesized powders, which is due to the fact that they not only possess the particle size of 11 nm without agglomeration, but also show high purity and good compositional uniformity.

Highlights

Since their discovery in 2015, high-entropy oxides, namely multicomponent ionic compounds, have been of considerable interest for their immense composition space, unique microstructure, adjustable properties, and great potential applications [1,2,3,4]
During the stage A, the precursor underwent a small amount of weight loss (~6%) with a very small endothermic peak below 200 °C, which could be attributed to the evaporation of water and residual solvents
This indicated that all kinds of organic matter for the precursor began to degrade and combust to generate the amorphous intermediates during this stage

Summary

Introduction

Since their discovery in 2015, high-entropy oxides, namely multicomponent ionic compounds, have been of considerable interest for their immense composition space, unique microstructure, adjustable properties, and great potential applications [1,2,3,4]. The high-entropy zirconates, a representative member of high-entropy fluorite oxides, have been attracting considerable research interest in recent years for their potential applications in the thermal barrier. Provided that the polymerized complex method is proposed to synthesize high-entropy zirconate nanopowders, it can be expected to achieve the lowtemperature synthesis of high-purity and superfine highentropy zirconate nanopowders without agglomeration, which improves the extensive applications of high-entropy zirconates. The polymerized complex method was proposed to synthesize the high-purity and superfine high-entropy zirconate nanopowders, namely (Y0.25La0.25Sm0.25Eu0.25)2Zr2O7 (RE2Zr2O7-1) nanopowders, without agglomeration at low temperatures, for the first time. The effect of synthesis temperature on the phase composition, crystallinity degree, lattice strain, and particle size of the as-synthesized powders was first studied, and the morphology, microstructure, and compositional uniformity of the as-synthesized powders were investigated in detail

Experimental

Results and discussion

Conclusions