Effect of an annealing treatment on the microstructure and EMW-absorbing properties of SiCw/Si3N4 ceramics fabricated by 3D printing. Issue 1 (1st January 2023)

• Record Type: Journal Article
• Authors: Yu, Siwen; Zeng, Tao; Yang, Yipeng; Jiang, Honghao; Wu, Rina; Fan, Meiling; Cheng, Su
• Is Part Of: Ceramics international. Volume 49:Issue 1(2023)
• Page Start: 1092
• Page End: 1101
• Publication Date: 2023-01-01
• Subjects: SiC whiskers/Si3N4 -- 3D-printing -- Annealing treatment -- Electromagnetic absorption; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.09.084
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: SiC whisker (SiCw )/Si3 N4 ceramics were prepared via selective laser sintering (SLS) and precursor infiltration pyrolysis (PIP) to achieve good electromagnetic wave (EMW) absorption performance. The as-pyrolyzed composite ceramics were annealed at 1200–1600 °C in a N2 atmosphere. The microstructural variation, phase evolution, and EMW-absorbing properties of the SiCw /Si3 N4 ceramics were subsequently studied. SiC whiskers were generated in the composite ceramics during pyrolysis, and their content increased as a function of the annealing temperature. An increase in the SiCw content of the annealed samples improved the reflection loss of the composite ceramics. The absorption properties of the SiCw /Si3 N4 ceramics first degraded and then improved with increasing annealing temperature. Among all the samples tested, the composite ceramics annealed at 1600 °C showed the optimal EMW absorption performance in the range of 2–18 GHz due to the lower content of free carbon and higher content of SiCw . The ceramics annealed at 1600 °C exhibited a superior absorption loss of −14.1 dB and an effective absorption bandwidth of 2.16 GHz. These results demonstrate that the EMW-absorbing performance of the SiCw /Si3 N4 ceramics was significantly improved after annealing at 1600 °C. Thus, SiCw /Si3 N4 composite parts with complex shapes were successfully manufactured by combining the SLS and PIP processes.