Ceramics-Silikáty 63, (1) 1 - 10 (2019) |
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MICROSTRUCTURE, MECHANICAL PROPERTIES AND FRICTION/WEAR BEHAVIOR OF HOT-PRESSED Si₃N₄/ BN CERAMIC COMPOSITES
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Chen Wei 1, Wang Zhaoxun 1, Gao Yimin 2, Li Huaqiang 3, He Nairu 1
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1 College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, Xi'an 710021, P.R. China
2 State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, P.R. China
3 Guangdong JOOYN New Material Technology Co.,Ltd., Xi'an 710065, P.R. China
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Keywords: Friction Mechanisms, Ceramic Composite, Unlubricated Wear, Silicon nitride (Si₃N₄) , Boron Nitride (BN)
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Nano-scale and micro-scale hexagonal boron nitride (hBN) powders, respectively, were added to silicon nitride (Si₃N₄) matrix powder, and Si₃N₄/BN ceramic composites with different content of solid-lubrication hBN were produced by hot pressing. The combined effect of starting powder and hBN content on the microstructure, mechanical properties and tribological properties of Si₃N₄/BN ceramic composites has been studied. The results showed that the nano-sized starting powder was beneficial to the densification of Si₃N₄/BN ceramic composites, and resulted in a Si₃N₄/BN nano/nano ceramic composite with slightly higher density and improved mechanical properties compared to the corresponding micro/nano ceramic composite. The physical and mechanical properties of Si₃N₄-based ceramic composites were found to be affected by addition of BN. Increasing BN content led to a decrease of bulk density, hardness, bending strength and fracture toughness. On the other hand, the starting powder has no significant influence on the tribological properties of Si₃N₄/BN ceramic composites. The friction properties and wear resistance continuously improved with increasing BN content up to 20 vol.%, due to the formation of tribochemical film composed of H₃BO₃, SiO₂ and metal oxides. |
 PDF (3.7 MB) |
doi: 10.13168/cs.2018.0040
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