Nickel silicides such as NiSi2 and Ni3Si display adequate structural and chemical properties for the heteroepitaxial HFCVD growth of diamond on it. Therefore, polycrystalline NiSi2 and Ni3Si were synthesized and their behavior for diamond growth were compared with polycrystalline references of Ni and Si samples. The quality of diamond particles grown on NiSi2 and Ni3Si as well as Si substrates is fairly increased in comparison with the quality of diamond grown on Ni substrates. This is interpreted from XPS and AES surface characterizations. by the depletion on Ni, Si of the graphitic layer observed on nickel which competes with diamond growth. Both on Si-rich NiSi2 silicide and silicon, a carbide is found as a precursor phase to diamond.