Ti-6Al-4V substrate has been coated with Ti 5 Si 3 or TiAl 3 intermetallic compound powder, and Inconel-700 with Ni 3 Ti and Ni 2 Al 3 to improve their oxidation and corrosion resistances. Micro-structural gradients to relief thermal stress is achieved though eutectic reactions in Ti-Ti 5 Si 3 and Ni-Ni 3 Ti systems while reaction diffusions in Ti-TiAl 3 and Ni-Ni 2 Al 3 peritectic systems. Microstructures of alloy substrates are controlled simultaneously during heat treatments for coating. In particular, Ti-6Al-4V/Ti 5 Si 3 and Inconel-700/NiAl functionally graded coatings (FGCs) have been fabricated successfully, so that no microscopic crackings have been detected.