Dielectric properties of spark plasma sintered AlN/SiC composite ceramics

Abstract

In this study, we have investigated how the dielectric loss tangent and permittivity of AlN ceramics are affected by factors such as powder mixing methods, milling time, sintering temperature, and the addition of a second conductive phase. All ceramic samples were prepared by spark plasma sintering (SPS) under a pressure of 30 MPa. AlN composite ceramics sintered with 30wt%–40wt% SiC at 1600°C for 5 min exhibited the best dielectric loss tangent, which is greater than 0.3. In addition to AlN and β-SiC, the samples also contained 2H-SiC and Fe₅Si₃, as detected by X-ray difraction (XRD). The relative densities of the sintered ceramics were higher than 93%. Experimental results indicate that nano-SiC has a strong capability of absorbing electromagnetic waves. The dielectric constant and dielectric loss of AlN-SiC ceramics with the same content of SiC decreased as the frequency of electromagnetic waves increased from 1 kHz to 1 MHz.

Keywords

ceramic materials / composite materials / aluminum nitride / silicon carbide / spark plasma sintering / dielectric losses

References

[1] Sbaizero O, Pezzotti G. Residual stresses and R-curve behavior of AlN/Mo composite. J. Eur. Ceram. Soc., 2001, 21(3): 269.

[2] Qiao L, Zhou HP, Fu RL. Thermal conductivity of AlN ceramics sintered with CaF₂ and YF₃. Ceram. Int., 2003, 29(8): 893.

[3] Komeya K, Inoue H, Tsuge A. Role of Y₂O₃ and SiO₂ additions in sintering of AlN. J. Am. Ceram. Soc., 1974, 57(9): 411.

[4] Komeya K, Tsuge A, Inoue H, Ohta H. Effect of CaCO₃ addition on the sintering of AlN. J. Mater. Sci. Lett., 1982, 1(8): 325.

[5] He XL, Ye F, Zhou ZQ, Zhang HJ. Thermal conductivity of spark plasma sintered AlN ceramics with multiple components sintering additive. J. Alloys Compd., 2010, 496(1–2): 413.

[6] Liu Y, Zhou H, Qiao L, Wu Y. Low-temperature sintering of aluminum nitride with YF₃-CaF₂ binary additive. J. Mater. Sci. Lett., 1999, 18(9): 703.

[7] Jarrige J, Bouzouita K, Doradoux C, Billy M. A new method for fabrication of dense aluminium nitride bodies at temperatures as low as 1600°C. J. Eur. Ceram. Soc., 1993, 12(4): 279.

[8] Qiao L, Zhou HP, Xue H, Wang SH. Effect of Y₂O₃ on low temperature sintering and thermal conductivity of AlN ceramics. J. Eur. Ceram. Soc., 2003, 23(1): 61.

[9] Peng Z, Bao YP, Chen YN, Yang LK, Xie C, Zhang F. Effects of calculation approaches for thermal conductivity on the simulation accuracy of billet continuous casting. Int. J. Miner. Metall. Mater., 2014, 21(1): 18.

[10] Chen H, Jia CC, Li SJ. Effect of sintering parameters on the microstructure and thermal conductivity of diamond/Cu composites prepared by high pressure and high temperature infiltration. Int. J. Miner. Metall. Mater., 2013, 20(2): 180.

[11] Pezzotti G, Nakahira A, Tajika M. Effect of extended annealing cycles on the thermal conductivity of AlN/Y₂O₃ ceramics. J. Eur. Ceram. Soc., 2000, 20(9): 1319.

[12] Shakeri MS. Effect of Y₂O₃ on the crystallization kinetics of TiO₂ nucleated LAS glass for the production of nanocrystalline transparent glass ceramics. Int. J. Miner. Metall. Mater., 2013, 20(5): 450.

[13] Cewen N. Heterogeneous Material Physics-Microstructure-Coherent Properties, 2005, Beijing, Science Press, 97

[14] Hotta M, Hojo J. Inhibition of grain growth in liquid-phase sintered SiC ceramics by AlN additive and spark plasma sintering. J. Eur. Ceram. Soc., 2010, 30(10): 2117.

[15] Zangvil A, Ruh R. Phase relationships in the silicon carbide-aluminum nitride system. J. Am. Ceram. Soc., 1988, 71(10): 884.

[16] Hotta M, Hojo J. Effect of AlN additive on densification, microstructure and strength of liquid-phase sintered SiC ceramics by spark plasma sintering. J. Ceram. Soc. Jpn., 2009, 117(9): 1009.

[17] Liu LD, Duan YP, Ma LX, Liu SH, Yu Z. Microwave absorption properties of a wave-absorbing coating employing carbonyl-iron powder and carbon black. Appl. Surf. Sci., 2010, 257(3): 842.

[18] Magnani G, Brillante A, Bilotti I, Beaulardi L, Trentini E. Effects of oxidation on surface stresses and mechanical properties of liquid phase pressureless-sintered SiC-AlN-Y₂O₃ ceramics. Mater. Sci. Eng. A, 2008, 486(1–2): 381.

[19] Boey F, Tok AIY, Lam YC, Chew SY. On the effects of secondary phase on thermal conductivity of AlN ceramic substrates using a microstructural modeling approach. Mater. Sci. Eng. A, 2002, 335(1–2): 281.

[20] Kusunose T, Sekino T, Niihara K. Production of a grain boundary phase as conducting pathway in insulating AlN ceramics. Acta Mater., 2007, 55(18): 6170.