Effect of cation dopants in zirconia on interfacial properties in nickel/zirconia systems: an atomistic modeling
Albert M Iskandarov1,2,3, Yingna Ding1, Yoshitaka Umeno1,2
1Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
Abstract:
Cation doping is often used to stabilize the cubic or tetragonal phase of zirconia for enhanced thermomechanical and electrochemical properties. In the present paper we report a combined density functional theory (DFT) and molecular dynamics study of the effect of Sc, Y, and Ce dopants on properties of Ni/[Formula: see text] interfaces and nickel sintering. First, we develop an MD model that is based on DFT data for various nickel/zirconia interfaces. Then, we employ the model to simulate Ni nanoparticles coalescing on a zirconia surface. The results show the possibility of particle migration by means of fast sliding over the surface when the work of separation is small (<[Formula: see text]). The sliding observed for the O-terminated Ni(1 1 1)/[Formula: see text](1 1 1) interface is not affected by dopants in zirconia because the work of separation of the doped interface stays small. The most pronounced effect of the dopants is observed for the Zr-terminated Ni(1 1 1)/[Formula: see text](1 1 1) interface, which possesses a large work of separation ([Formula: see text]) and thus restricts the sliding mechanism of Ni nanoparticle migration. DFT calculations for the interface revealed that dopants with a smaller covalent radius result in a larger energy barriers for Ni diffusion. We analyze this effect and discuss how it can be used to suppress nickel sintering by using the dopant selection.
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