Rufei Chen,Wenyan Duan,Gong Wang,Bingshan Liu,Yantong Zhao,Shan Li
Wave-transmitting materials are a kind of multi-functional materials that protect the normal operation of communication and guidance systems of spacecraft in harsh environments. In this paper, we fabricate a broadband microwave transparent Si 3 N 4 -SiO 2 composite ceramic with excellent performance through digital light processing (DLP) 3D printing technology. The influences of sintering temperature on the weight increase rate, density, dimensional shrinkage, phase composition, microstructure, bending strength and dielectric properties of Si 3 N 4 -SiO 2 ceramic were all systematically studied. The strength of Si 3 N 4 -SiO 2 ceramic sintered at 1350 ℃ was 77 ± 5 MPa. The relative permittivity of the ceramic is within the range of less than 4, and the loss tangent can be below 0.003. The 3D printed Si 3 N 4 -SiO 2 ceramic material exhibited excellent wave-transparent performance.
Xingjie Dong,Jianqin Wu,Qing Zhou,Wenqing Wang,Xueqin Zhang,Lu Zhang,Rujie He
Si 3 N 4 -SiO 2 ceramics are considered as the preferred high-performance wave-transmitting material in the aerospace field. However, traditional fabrication methods for Si 3 N 4 -SiO 2 ceramics have the disadvantages of high cost and complicated fabrication process. In this paper, Si 3 N 4 -SiO 2 ceramics with excellent mechanical and dielectric properties were fabricated by digital light processing-based 3D printing combined with oxidation sintering. Firstly, the curing thickness and viscosity of slurries with different solid loadings for vat photopolymerization-based 3D printing were studied. Then, the effects of the sintering temperature on the linear shrinkage, phase composition, microstructure, flexural strength , and dielectric properties of Si 3 N 4 -SiO 2 ceramics, and the influences of solid loading on them were explored. The curing thickness and viscosity of the slurry with a solid loading of 55 vol% were 30 μm and ∼1.5 Pa‧s, respectively. The open porosity and the flexural strength of Si 3 N 4 -SiO 2 ceramic with a solid loading of 55 vol% were 4.3 ± 0.61% and 76 ± 5.6 MPa, respectively. In the electromagnetic wave band of 8–18 GHz, the dielectric constant of Si 3 N 4 -SiO 2 ceramics was within the range of less than 4, and the dielectric loss remained below 0.09. The method of digital light processing-based 3D printing combined with oxidation sintering can be further extended in the preparation of Si 3 N 4 -based structure-function integrated ceramics.
危险品化学品经营许可证（带存储）