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以α-Si_3N_4粉、β-SiC_W为原料,Al_2O_3、Y_2O_3为烧结助剂,采用凝胶注模工艺制备了SiC_W/Si_3N_4复合陶瓷材料,烧结温度为1 650℃,保温1.5h。研究了SiC_W加入含量对SiC_W/Si_3N_4复合陶瓷的微观结构、力学及常温/高温微波吸收性能的影响。结果表明:随着SiC_W含量的增加,SiC_W/Si_3N_4复合陶瓷的抗弯强度和断裂韧性都有先増后减的趋势,当含量为10wt%时,抗弯强度达到最大值505MPa,断裂韧性达9.515MPa·m1/2。常温介电常数在SiC_W含量为10wt%时,实部达最大值12,在12GHz最大吸收值为-21dB。高温介电常数随着SiC_W含量的增加有先增后减的趋势,在含量为10wt%时,实部达到最大值12.5。相比于纯Si_3N_4陶瓷,当SiC_W含量为10wt%时,SiC_W/Si_3N_4复合陶瓷在11.7GHz左右最大吸收可达-27dB,有效吸收频带(小于-5dB)为11.2~12.3GHz。
SiC_W / Si_3N_4 composite ceramics were prepared by the gel-casting process with α-Si_3N_4 powder and β-SiC_W as raw materials and Al_2O_3 and Y_2O_3 as sintering aids. The sintering temperature was 1 650 ℃ and the thermal insulation was 1.5h. The effects of SiC_W content on the microstructure, mechanical properties and microwave absorption properties of SiC_W / Si_3N_4 composite ceramics were investigated. The results show that with the increase of SiC_W content, the bending strength and fracture toughness of SiC_W / Si_3N_4 composite ceramics increase first and then decrease. When the content is 10wt%, the flexural strength reaches 505MPa and the fracture toughness reaches 9.515 MPa · m1 / 2. Dielectric constant at room temperature SiC_W content of 10wt%, the real part of the maximum 12, 12GHz maximum absorption value of-21dB. The dielectric constant of high temperature increases first and then decreases with the increase of SiC_W content. When the content is 10wt%, the real part reaches the maximum value of 12.5. Compared with pure Si_3N_4 ceramics, SiC_W / Si_3N_4 composite ceramics have a maximum absorption of -27dB at 11.7GHz and an effective absorption band (less than -5dB) of 11.2-12.3GHz when SiC_W content is 10wt%.