Phase analysis and thermal conductivity of in situ O′-sialon/β-Si₃N₄ composites

Abstract

Typical O′-sialon-based ceramics, with a formula of Si_2−xAl _xO_1+xN_2−x, where x was set as 0.25, were fabricated by in-situ synthesis. Si₃N₄, Al₂O₃, and SiO₂ powders were used as raw materials, and MgO and Y₂O₃ were added as sintering additives. All the samples were sintered at different temperatures under a nitrogen pressure of 0.25–0.30 MPa, and their microstructure, phase content, and thermal conductivity were evaluated. The effects of O′-sialon and β-Si₃N₄ on the thermal conductivity were analyzed by numerical calculation in detail. In the case of the similar porosity, the thermal conductivity of O′-sialon-based ceramics decreased with the ratio of O′-sialon/β-Si₃N₄ increasing. When the ratio was 12, the thermal conductivity of O′-sialon ceramics sintered at 1360°C was 1.197 W·m⁻¹·K⁻¹.

Keywords

ceramic materials / sintering / phase composition / thermal conductivity / numerical calculation

References

[1] Izhevskiy V.A., Genova L.A., Bressiani J.C., Aldinger F. Progress in SIALON ceramics. J. Eur. Ceram. Soc., 2000, 20, 2275

[2] Alcala M.D., Criado J.M., Gotor F.J., Real C. β-Si₃N₄ obtained from carbothermal reduction of kaolinite employing samples controlled reaction temperature (SCRT). J. Mater. Sci., 2006, 41, 1933

[3] Oyama Y., Kamigaito K. Solid solubility of some oxides in Si₃N₄. Jpn. J. Appl. Phys., 1971, 10, 1637

[4] Jack K.H., Wilson W.I. Ceramics based on the Si-Al-O-N and related systems. Nat. Phys. Sci., 1977, 238, 28.

[5] Yi X.M., Yamauchi A., Kurokawa K., Akiyama T. Oxidation of β-SiAlONs prepared by a combination synthesis and spark plasma sintering. Corros. Sci., 2010, 52, 1738

[6] Chou K.C. A kinetic model for oxidation of Si-Al-O-N materials. J. Am. Ceram. Soc., 2006, 89, 1568

[7] Hou X.M., Chou C.K., Li F.S. Some new perspectives on oxidation kinetics of SIALON materials. J. Eur. Ceram. Soc., 2008, 28, 1243

[8] Mackenzie K.J.D., Shimada S., Aoki T. Thermal oxidation of carbothermal β′-sialon powder: reaction sequence and kinetics. J. Mater. Chem., 1997, 7, 527

[9] Mackenzie K.J.D., Sheppard C.M., Barris G.C., Mills A.M., Shimada S., Kiyono H. Kinetics and mechanism of thermal oxidation of sialon ceramic powders. Thermochim. Acta, 1998, 318, 91

[10] Hayashi H., Hirao K., Toriyama M., Kanzaki S. MgSiN₂ addition as a means of increasing the thermal conductivity of β-Silicon nitride. J. Am. Ceram. Soc., 2001, 84, 3060

[11] Zhu X., Zhou Y., Hirao K. Effect of processing method and additive composition on microstructure and thermal conductivity of Si₃N₄ ceramics. J. Eur. Ceram. Soc., 2006, 26, 711

[12] Zhu X., Zhou Y., Hirao K., Lenčéš Z. Processing and thermal conductivity of sintered reaction-bonded silicon nitride: I. Effect of Si powder characteristics. J. Am. Ceram. Soc., 2006, 89, 3331

[13] Kitayama M., Hirao K., Tsuge A., Watari K., Toriyama M., Kanzaki S. Thermal conductivity of β-Si₃N₄: II. Effect of lattice oxygen. J. Am. Ceram. Soc., 2000, 83, 1985

[14] Hiroshi Y., Masahiro I. Effect of lattice impurities on thermal conductivity of β-Si₃N₄. J. Eur. Ceram. Soc., 2003, 23, 55

[15] Yokota H., Ibukiyama M. Effect of addition of β-Si₃N₄ nuclei on the thermal conductivity of β-Si₃N₄ ceramics. J. Eur. Ceram. Soc., 2003, 23, 1183

[16] Yokota H., Ibukiyama M. Microstructure tailoring for high thermal conductivity of β-Si₃N₄ ceramics. J. Am. Ceram. Soc., 2003, 86, 197

[17] Ke C., Edrees J.J., Hendry A. Fabrication and microstructure of sialon-bonded silicon carbide. J. Eur. Ceram. Soc., 1999, 19, 2165

[18] Xu X.W., Liang H., Li X.L., Ji H.M., Wan Y.Z. In situ synthesis and phase analysis of low density O′-sialon-based multiphase ceramics. Rare Met., 2010, 29, 214