Synthesis of SiC@Al2O3 core–shell nanoparticles for dense SiC sintering--颗粒学报PARTICUOLOGY

Liu, Y., Liu, R., Liu, M., & Chang, J. (2019). Synthesis of SiC@Al2O3 core–shell nanoparticles for dense SiC sintering. Particuology, 44, 80-89. https://doi.org/10.1016/j.partic.2018.08.010

Synthesis of SiC@Al₂O₃ core–shell nanoparticles for dense SiC sintering

Yiteng Liu, Rongzheng Liu, Malin Liu ^*, Jiaxing Chang

Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China

10.1016/j.partic.2018.08.010

Volume 44, June 2019, Pages 80-89

Received 1 July 2018, Revised 28 July 2018, Accepted 30 August 2018, Available online 18 February 2019, Version of Record 30 April 2019.

E-mail: liumalin@mail.tsinghua.edu.cn

Highlights

• A core–shell structure of SiC@Al₂O₃ nanoparticles is designed and prepared.

• Sintering of dense SiC matrix by slow co-precipitation method is optimized.

• The SiC@Al₂O₃ nanoparticles exhibit better sintering properties.

• The optimized parameters to obtain a dense sintered SiC matrix are determined.

Abstract

Owing to the difficulty for dense SiC sintering, high sintering temperatures and pressures are usually needed. Lowering the sintering temperature by adding Al₂O₃ as a sintering additive has previously been shown to be beneficial. However, traditional addition methods limit the effect of the Al₂O₃ owing to inhomogeneous mixing at the nanoscale. A SiC@Al₂O₃ composite nanoparticle with a core–shell structure is designed and prepared using the slow co-precipitation method. The differences between this method and the traditional mechanical ball milling method are interpreted by different experimental parameters, such as temperature, pressure, amount of additive, and mixing type. It is found that the method of slow co-precipitation enables homogeneous mixing of Al₂O₃ and SiC at a smaller scale, and makes the sintered SiC much denser and more homogeneous, when compared with the traditional method. The parameters of sintering at 1900 °C and 30 MPa for 30 min are recommended. The conclusions here are also beneficial for the sintering research of other ceramic materials.

Graphical abstract

Keywords

Core–shell nanoparticles; Dense sintering; SiC; Coating; Hot-pressing

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