Silicon Nitride Single Crystals Mechanical Properties

Silicon Nitride Single Crystals Mechanical Properties 2.1.4.1 a-Si3N4 

A molecular dynamics (MD) calculation of the ideal thermal conductivity of a-Si3N4 single crystal provided values of 105 and 225 Wm K , respectively [40]. 

The thermal expansion coefficient of [3-Si3N4 depends on its crystallographic orientation, with values of 3.23 x 10 being determined for the basal plane and 3.72 X 10 for the prismatic plane, within a temperature range from 0 to 1000 °C [35]. Similar values were determined by Bruls et al. [44]. 

The ideal tensile strength of [3-Si3N4 single crystal obtained by ah initio calculations [45, 46] was 57 GPa, with an estimated hardness of 20.4 GPa. The latter value 

The density of P-Si3N4, as calculated from the structural data of the single crystal, was 3.214gcm [14], while that for polycrystaDine P-Si3N4 was 3.202 gcm [44]. 

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Aluminum nitride (AlN) has interesting properties, such as a high thermal conductivity (70-210 W m for the polycrystalline material, and up to 285 W m for single crystals), a high volume resistance, and moderate dielectric properties. The thermal expansion coefficient of AlN is close to that of silicon, and it is one of the most mechanically strong and thermally stable ceramics. These excellent attributes make AlN a useful material for many applications [160, 161]. 

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