@article{CHEN2022, 
author = {Zhiwei CHEN and Weiming GUO and Sichun LUO and Huatai LIN},
title = {High Hardness and High Toughness Si3N4–SiCw–ZrB2 Ceramics Prepared by Low-Temperature Hot Pressing},
year = {2022},
journal = {Journal of the Chinese Ceramic Society},
volume = {50},
number = {6},
pages = {1527-1532},
keywords = {silicon nitride, silicon carbide whisker, zirconium boride, low temperature hot pressing, microstructure, mechanical properties},
url = {https://www.sciopen.com/article/10.14062/j.issn.0454-5648.20210844},
doi = {10.14062/j.issn.0454-5648.20210844},
abstract = {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 1500 ℃ 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 1800 ℃ . The results show that the addition of SiCw inhibits the densification of Si3N4 ceramics sintered at 1500 ℃ , 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.}
}