Thermal expansion studies of the group IV-VII transition-metal disilicides

Abstract

The thermal expansions of the group IV-VII transition-metal disilicides and Mn15Si26 have been investigated from room temperature to about 1500 K by x-ray powder-diffraction techniques. The results are discussed in relation to the structure of the compounds. Most of the disilicides studied exhibit a high degree of thermal expansion isotropy, exceptions being ZrSi2, HfSi2, and CrSi2. The observed linear thermal expansion coefficients are normally in the range 8–9×10−6 K−1 (298 K) to 11–15×10−6 K−1 (1300 K). The most extreme expansion was exhibited by CrSi2 with a linear expansion coefficient of 22×10−6 K−1 for the a axis at 1300 K.