Journal of the Chinese Ceramic Society, Volume. 50, Issue 6, 1527(2022)

High Hardness and High Toughness Si3N4-SiCw-ZrB2 Ceramics Prepared by Low-Temperature Hot Pressing\

CHEN Zhiwei*... GUO Weiming, LUO Sichun and LIN Huatai |Show fewer author(s)
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    Low-temperature hot pressed Si3N4 ceramics show a greater Vickers hardness and a lower fracture toughness, while high-temperature hot pressed Si3N4 ceramics show a lower Vickers hardness and a higher fracture toughness. To prepare Si3N4 ceramics with a great Vickers hardness and a high fracture toughness, a low-temperature hot pressed Si3N4 ceramic was prepared via sintering at 1 500 ℃ with 20% SiC whisker (SiCw, in volume fraction) and 2.5% ZrB2. The phase composition, relative density, microstructure and mechanical properties of low-temperature hot pressed Si3N4 ceramic were investigated, compared with high-temperature hot pressed Si3N4 ceramics at 1 800 ℃. The results show that the addition of SiCw inhibits the densification of Si3N4 ceramics sintered at 1 500 ℃, and the relative density decreases from 97.9% to 92.9%, the Vickers hardness decreases from 20.5 GPa to 16.4 GPa, and the fracture toughness increases from 2.9 MPa·m1/2 to 3.4 MPa·m1/2. However, the addition of SiCw and ZrB2 promotes the phase transition from α-Si3N4 to β-Si3N4. The relative density of Si3N4-SiCw-ZrB2 reaches 97.5%, and the Vickers hardness and fracture toughness are 20.7 GPa and 5.1 MPa·m1/2, respectively. Compared with low-temperature hot pressed Si3N4 ceramic, the fracture toughness of Si3N4-SiCw-ZrB2 ceramic is improved without reducing the Vickers hardness. Compared with high-temperature hot pressed Si3N4 ceramic, the hardness is greatly improved. The Si3N4-based ceramic with high hardness and toughness prepared via a low-temperature hot pressing with SiCw and ZrB2 can have a promising application in ceramic structural parts.

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    CHEN Zhiwei, GUO Weiming, LUO Sichun, LIN Huatai. High Hardness and High Toughness Si3N4-SiCw-ZrB2 Ceramics Prepared by Low-Temperature Hot Pressing\[J]. Journal of the Chinese Ceramic Society, 2022, 50(6): 1527

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    Paper Information

    Category:

    Received: Sep. 29, 2021

    Accepted: --

    Published Online: Dec. 6, 2022

    The Author Email: Zhiwei CHEN (czwlkif@163.com)

    DOI:

    CSTR:32186.14.

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