Fig. 1. Scanning electron microscopy images of the Si3N4 ceramics. (a) Plasma-etched surface of SP0, (b) Polished surface of SP16, (c) magnified image of SP16 and (d) fracture surface of SB16
Fig. 2. X-ray diffraction(XRD) patterns of the SP16 and SB16. Comparison with the JCPDS data of Si3N4 and BN
Fig. 3. Effect of PMMA and BN content on the flexural strength of the Si3N4 ceramics
Fig. 4. Effect of PMMA and BN content on the dielectric constant of the Si3N4 ceramics. The inset table lists the loss tangent of the composition
Fig. 5. Data map of flexural strength and dielectri cconstant of SP and SB compositions
Table 1. Identification, PMMA contents, density and porosity of the SP compositions
Table 2. Identification, BN contents, density and porosity of the SB compositions
References
- F. L. Riley, "Silicon Nitride and Related Materials," Journal of the American Ceramic Society, Vol. 83, Issue 2, pp. 245-165, 2000. https://doi.org/10.1111/j.1151-2916.2000.tb01182.x
- F. Chen, Q, Shen, L. Zhang, "Electromagnetic Optimal Design and Preparation of Broadband Ceramic Radome Materials with Graded Porous Structure," Progress in Electromagnetic Research, Vol. 105, pp. 445-461, 2010.
-
S. J. Lee, S. Baek, "Effect of
$SiO_2$ Content on the Microstructure, Mechanical and Dielectric Properties of$Si_3N_4$ Ceramics," Ceramics International, Vol. 42, Issue 8, pp. 9921-9925, 2016. https://doi.org/10.1016/j.ceramint.2016.03.092 - J. D. Walton, "Radome Engineering Handbook," Marcel Dekker, INC., New York, pp. 229-344, 1970.
- K. K. Kärkkäinen, A. H. Sihvola, K. I. Nikoskinen, “Effective Permittivity of Mixture: Numerical Validation by the FDTD Method,” IEEE Transactions on Geoscience and Remote Sensing, Vol. 38, No. 3, pp. 1303-1308, 2000. https://doi.org/10.1109/36.843023
- W. D. Kingery, H. K. Bowen, D. R. Ulhann, "Introduction to Ceramics," John Wiley & Sons, Inc. New York, 2nd Edition, pp. 808-812, 1976.
- J. F. Yang, T. Ohji, "Influence of Yttria-Alumina on Sintering Behavior and Microstructure of Silicon Nitride Ceramics," Journal of the American Ceramic Society, Vol. 83, Issue 8, pp. 2094-2096, 2000. https://doi.org/10.1111/j.1151-2916.2000.tb01520.x
- S. Hampshire, "Silicon Nitride Ceramics - Review of Structure, Processing and Properties," Journal of Achievements in Materials and Manufacturing Engineering, Vol. 24, Issue 1, pp. 43-50, 2007.
- P. Wu, Y. Xu, Z. Huang, J. Zhang, “A Review of Preparation Techniques of Porous Ceramics Membranes,” Journal of Ceramic Processing Research, Vol. 16, No. 1, pp. 102-106, 2015.
-
D. Wei, Q. Meng, D. Jia, "Microstructure of Hotpressed h-BN/
$Si_3N_4$ Ceramic Composite with$Y_2O_3$ -$Al_2O_3$ Sintering Additive," Ceramics International, Vol. 33, pp. 221-226, 2007. https://doi.org/10.1016/j.ceramint.2005.09.004 - T. Kusunose, T. Sekino, Y. H. Choa, K. Niihara, "Fabrication and Microstructure of Silicon Nitride/ Boron Nitride Nanocomposites," Journal of the American Ceramic Society, Vol. 85, Issue 11, pp. 2678-2688, 2002 https://doi.org/10.1111/j.1151-2916.2002.tb00514.x
- S-H. Kim, Y-H. Lee, W-S. Cho, J-G. Kim, M-W. Cho, E-S. Lee, J-H. Lee, “Effect of h-BN Content on Microstructure and Mechanical Properties of Si3N4,” Journal of the Korean Ceramic Society, Vol. 40, No. 9, pp. 867-873, 2003. https://doi.org/10.4191/KCERS.2003.40.9.867
- J. Yang, J-F. Yang, S-Y. Shan, J-Q. Gao, T. Ohji, "Effect of Sintering Additives on Microstructure and Mechanical Properties of Porous Silicon Nitride Ceramics," Journal of the American Ceramic Society, Vol. 89, Issue 12, pp. 3843-3845, 2006. https://doi.org/10.1111/j.1551-2916.2006.01294.x
- Y. Yacubowicz, M. Narkis, L. Benguigui, “Electrical and Dielectric Properties of Segregated Carbon Black-Polyethylene Systems,” Polymer Engineering and Science, Vol. 30, No. 8, pp. 459-468, 1990. https://doi.org/10.1002/pen.760300806
- T. Fateh, F. Richard, T. Rogaume, P. Joseph, "Experimental and Modelling Studies on the Kinetics and Mechanisms of Thermal Degradation of Polymethyl Methacrylate in Nitrogen and Air," Journal of Analytical and Applied Pyrolysis, Vol. 120, pp. 423-433, 2016. https://doi.org/10.1016/j.jaap.2016.06.014