The effect of Al2O3, Y2O3 and ZrO2 coating materials to the Ti-48Al alloys on the metal-coating interface, alloy chemical composition and microstructure is evaluated by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis, respectively. Microhardness variation from the surface to the inside of the samples was compared. The results indicate that inordinate interaction occurred at the interface between the coating and the melt. The crucible layer was found to suffer chemical dissolution and some physical erosion by the molten alloy and the extent of that dissolution, depend partly on the coating material. Additionally, The thermodynamics of the TiAl/Oxide reactions have been studied, and the main mechanism responsible for the contamination of the directional solidification samples is diffusion controlled dissolution of the coatings in the melt which leads to an increase of oxygen content in the matrix.