Polymorphism of Ti₃SiC₂

We investigated the crystal structure of Ti₃SiC₂ by means of high-resolution electron microscopy (HREM). Two polymorphs, α– and β–Ti₃SiC₂, were identified. The amount of the α phase was larger than the β phase, indicating that the former has lower energy than the latter. We also found that the bright spots in HREM images of Ti₃SiC₂ do not necessarily correspond to the atomic columns; thus an intuitive interpretation of the image contrast in terms of the stacking sequences of the close-packed layers should be made cautiously