Thermodynamic and Dielectric Properties of MgSiN2 Ceramics


Article Preview

Reaction bonded MgSiN2 (RBMSN) was prepared by direct nitridation of a Si/Mg2Si/Mg/Si3N4 powder compact in a temperature range of 1350-1550°C. The oxygen content of MgSiN2 was in the range of 0.4 – 0.6 wt%. A thermal stability examination showed that MgSiN2 is stable up to 1400°C at 0.1 MPa N2 pressure. The activation energy of decomposition calculated from the temperature dependence of weight loss is H = 383 kJ⋅mol-1. The time dependence and nitrogen pressure dependence of MgSiN2 decomposition was also investigated at constant temperature. MgSiN2 is stable at 1560°C in 0.6 MPa nitrogen atmosphere. Using these experimental data together with the heat capacity published in a literature the Gibbs free energy of formation of MgSiN2 was calculated in a temperature range 300-2500 K. Dense MgSiN2 ceramics or MgSiN2/Si3N4 composites with fluorine-based additives were prepared by hot pressing. The composite materials had a 4-point bending strength of 427 MPa and Vickers hardness (HV1) of 20.8 GPa, respectively. The indentation fracture toughness was 5.3 MPa.m1/2, due to the presence of elongated β-Si3N4 grains. The dielectric constant of dense reaction bonded MgSiN2 at 100 kHz was 9.5-10, while that of MgSiN2/Si3N4 composite in a wide range 50 – 6000, depending on composition and heat treatment.



Key Engineering Materials (Volumes 317-318)

Edited by:

T. Ohji, T. Sekino and K. Niihara






Z. Lenčéš et al., "Thermodynamic and Dielectric Properties of MgSiN2 Ceramics", Key Engineering Materials, Vols. 317-318, pp. 857-860, 2006

Online since:

August 2006




[1] H. Hayashi, K. Hirao, M. Toriyama, S. Kanzaki and K. Itatani: J. Am. Ceram. Soc., Vol. 84, (2001), 3060-62.

[2] R.J. Bruls, H.T. Hintzen, and R. Metselaar: J. Mater. Sci., Vol. 34, (1999), 4519-31.

[3] W.A. Groen, M.J. Kraan, and G. de With: J. Eur. Ceram. Soc., Vol. 12, (1993), 413-20.

[4] H. Uchida, K. Itatani, M. Aizawa, F.S. Howell, A. Kishioka: J. Ceram. Soc. Japan, Vol. 105.

[11] (1997), 934-39.

[5] Z. Lenčéš, K. Hirao, Y. Yamauchi, S. Kanzaki: J. Am. Ceram. Soc., 86, (2003), 1088-93.

[6] J. David, Y. Laurent and J. Lang: Bull. Soc. Fr. Mineral. Cristall., Vol. 93, (1970), 153-59.

[7] R.J. Bruls, H.T. Hintzen, R. Metselaar, J.C. van Miltenburg: J. Phys. Chem. B., Vol. 102, (1998), 7871-76.

[8] R.J. Bruls, H.T. Hintzen, G. de With, R. Metselaar, J.C. van Miltenburg: J. Phys. Chem. Solids, Vol. 62, (2001), 783-92.

[9] M.W. Chase Jr.: NIST-JANAF Thermochemical Tables, Fourth Edition, Journal of Physical and Chemical Reference, Monograph 9 (1998).

In order to see related information, you need to Login.