Abstract
The n-SiC (nanometer SiC) is added to be the additive in order to improve the mechanical performance of Si3N4 ceramics. A microwave sintered the ceramics at different temperature and holding times. The results shows that the Si3N4/n-SiC ceramics (85 wt% Si3N4 + 5 wt% n-SiC + 5 wt% Al2O3 + 5 wt% Y2O3) have the best mechanical properties at 1600 °C, which is beneficial to the densification and β-Si3N4 phase formation for 10 min: the density, hardness, and fracture toughness were 97.1%, 14.44 GPa, and 7.77 MPa·m1/2, which increased by 2.8%, 7.0%, and 13.1%, respectively, when compared with the ceramics (90 wt% Si3N4 + 5 wt% Al2O3 + 5 wt% Y2O3).
Highlights
Si3 N4 ceramic have been widely recognized as the ideal tool materials for cutting the high temperature cast iron and nickel-based alloys due to its outstanding thermal properties, wear resistance, and high temperature material properties [1,2,3,4]
When considering that n-SiC has good microwave absorption properties and high hardness at all temperature stages [18], it is added into silicon nitride ceramics
When n-SiC is not added into the sintered silicon nitride materials, the density, Vickers hardness, and fracture toughness of the Si3 N4 ceramics are 94.5%, 13.5 GPa, and 6.87 MPa·m1/2, which hardness, and fracture toughness of the Si3N4 ceramics are 94.5%, 13.5 GPa, and 6.87 MPa·m, which increased by 2.6%, 7.0%, and 13.1%, respectively
Summary
Si3 N4 ceramic have been widely recognized as the ideal tool materials for cutting the high temperature cast iron and nickel-based alloys due to its outstanding thermal properties, wear resistance, and high temperature material properties [1,2,3,4]. Many researches have shown that it can promote the densification of sintered materials to short the sintering time, and refine the crystalline microstructure [14,15,16,17]. As a result of that these two kinds of sintering additives can contribute to the formation of the liquid phase, which can promote the densification of Si3N4 ceramics, we selected these sintering aids in our research. The effects of sintering temperature and holding time on the properties of microwave sintered Si3N4/n-SiC ceramics were analyzed. SEM microstructure analysis, X-ray diffraction (XRD) phase analysis, density, and hardness and fracture and Y2 O3 were used as sintering additives, for example, Tiegs et al [24] successfully sintered toughness.
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