Research on Mechanical Properties of SiC/Si3N4 Composites Prepared by Hot Pressing Sintering
SIC/SI3N4 ceramic composites were prepared by hot pressing sintering and the effect of temperature and pressure on the mechanical properties and microstructure of the composites were studied.The results showed that:(1)With the mass ratio of Si3N4:SiC:CaF2=6:4:1,the bending strength of the material at 1 400 ℃ and 25 MPa reaches the maximum of 66.7 MPa,the bulk density is 2.2 g/cm3,and the porosity is 29.01％.As the temperature rises,the properties of the material gradually decline.At 1 400 ℃,the main crystalline phase is still[3-Si3N4 and contains a small amount of SiC.(2)Under the same mass ratio,sintering temperature of 1 400 ℃ and the sintering pressure of 45 MPa,the mechanical properties of the composite can reach 77.4 MPa,the bulk density can reach 2.3 g/cm3,and the porosity can reach 27.09％.It can be observed from the SEM diagram that the density and mechanical properties of the material gradually increase with the increasing of sintering pressure.
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