Thermal expansion of spinel-type Si3N4

Abstract

The lattice parameter and thermal expansion coefficient (TEC) for the spinel-type Si3N4 phase prepared under high-pressure and high-temperature conditions are determined for 14K < T < 302Kby x-ray diffraction, at a synchrotron-radiation source, and for 0K < T < 1683K by first-principles calculations. The low- and high-temperature experimental TEC data are in excellent agreement with the calculations. Our results provide the first experimental evidence that the linear expansion coefficient tends to vanish for T < 100K. The experimental temperature dependence of the TEC is accurately represented by polynomials over the complete T range. © 2004 The American Physical Society.