Centimetric CrSi2 crystal grown by the vertical gradient Freeze method

Abstract

CrSi2 ingots were grown by the Vertical Gradient Freeze (VGF) method in silica (SiO2) crucibles with boron nitride (BN) coating and in pyrolytic boron nitride (pBN) crucibles in order to minimize the sticking and the reaction with the molten Cr-Si alloy. High quality chromium disilicide single crystal was obtained with a mosaicity of 1–2° using pBN crucible with a thermal gradient of 0.6 K/mm and a growth rate of 10 mm/h. To recycle the crucibles and so to reduce the production costs, pBN crucibles were cleaned with hydrofluoric acid solution. As a result of this treatment, it was not possible to obtain CrSi2 single crystals due to a modification of the crucible surface and the subsequent increase of boron compounds in the melt during the growth. The effect of the growth conditions on the microstructure of polycrystalline sample was also investigated using the texture analysis technique.