Specific surface free energy and the morphology of synthesized ruby single crystals

Abstract Ruby single crystals were synthesized from Mo- or Pb-based fluxes. The specific surface free energy of crystal was experimentally obtained using contact angle of liquid droplets on the crystal surface, and compared with the equilibrium grown length of each face. The proportion of the specific surface free energy and the equilibrium grown length was constant for the different faces of each individual ruby crystal, which looks to satisfy Wulff’s relationship. The relationship between specific surface free energy of the faces of the individual crystal with the same index and the equilibrium grown length of the face was linier. The difference in the specific surface free energy for the face of the same index can be explained by the difference in step length.