Study of Nickel Segregation at the TiNi-Titanium oxide interface

摘要

Ab-intio study of atomic and molecular oxygen interaction with TiNi(110) surface are performed by using the projector augmented wave method with generalized gradient approximation for the exchange-correlation functional. Our results confirm the formation of a Ni-rich layer at the alloy-oxide interface, for which the formation energies (H_f) of point defects at the interfacial layers were estimated. It is shown that H_f of swap Ti-Ni defect has a lower energy than that for the Ni antisites at the interfacial layers. The formation energies of point defects in bulk TiNi, monoclinic TiO, and rutile TiO_2 are also calculated. Our results demonstrate that H_f of Ni-antisites in TiO is twice less than that in TiO_2. The formation of small Ni clusters in titanium oxides is also discussed.