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Reaction Synthesis and Mechanical Properties of Lu4Si2O7N2

Authors

  • Luchao Sun,

    1. High-performance Ceramics Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
    2. Graduate School of Chinese Academy of Sciences, Beijing, China
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  • Mingyue Liu,

    1. High-performance Ceramics Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
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  • Liya Zheng,

    1. High-performance Ceramics Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
    2. Graduate School of Chinese Academy of Sciences, Beijing, China
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  • Xinpo Lu,

    1. High-performance Ceramics Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
    2. Graduate School of Chinese Academy of Sciences, Beijing, China
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  • Jingyang Wang,

    Corresponding author
    • High-performance Ceramics Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
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  • Zijun Hu

    1. Aerospace Research Institute of Materials and Processing Technology, Beijing, China
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Author to whom correspondence should be addressed. e-mail: jywang@imr.ac.cn

Abstract

Crystallized LuSiON phases were believed to be the grain-boundary (GB) phases that might provide Si3N4 with excellent high-temperature mechanical properties. However, little is known about the intrinsic properties, as well as the synthesis, of the LuSiON ceramics. This work reveals the reaction paths of heating Lu2O3, SiO2, and Si3N4 powder mixtures (with the stoichiometry of 4:0.96:1) from room temperature to 1600°C. Thereafter, dense Lu4Si2O7N2 samples are synthesized by in situ reaction/hot-pressing method, and the mechanical properties at room temperature and elevated temperatures are reported for the first time. The Lu4Si2O7N2 samples show significant high-temperature mechanical properties, such as the elastic stiffness remains 77% from room temperature to 1500°C; and bending strength keeps 93% from room temperature to 1400°C. The present results shine a light on Lu4Si2O7N2 as a promising target GB phase for the optimization of high-temperature mechanical properties of Si3N4.

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