On the thermal expansion coefficient of CoSi2 and NiSi2

We have accurately determined the thermal expansion coefficients of CoSi(2) and NiSi(2) using high-temperature x-ray diffraction in the temperature range 300-850 K, resolving the ambiguity in the values reported in the literature. The room temperature (298 K) linear thermal expansion coefficients (alpha = (1/a(0))(partial derivative a/partial derivative T)) for CoSi(2) and NiSi(2) are found to be alpha CoSi(2) = 14.4 +/- 0.6 x 10(-6)K(-1) and alpha(NiSi2) = 14.4 +/- 0.7 x 10(-6) K(-1), respectively. Our results, however, strongly suggest that the thermal expansion coefficient of NiSi(2) is temperature dependent and we recommend to use alpha(NiSi2) (T) = [(14.3 +/- 0.5) + (0.006 +/- 0.002) (T - 273K)] x 10(-6) K(-1) whenever an accurate value of the NiSi(2) thermal expansion coefficient is needed.