Investigation on grain refinement mechanism of Ni-based coating with LaAlO3 by first-principles

In this work, the adhesion energy, interfacial energy, interface bonding and interface magnetism of LaA103/Ni interface were calculated by the first-principles method. Meanwhile, the effectiveness of LaAlO3 as the heterogeneous nucleus of Ni grains was also analyzed. The results show that the Wad of the AlO2-O-OT interface is the largest, which is 3.58 J/m(2). Those of the LaO-OT interface and AlO2-Al-OT interface are followed. While that of the LaO-MT interface is the smallest. Interface magnetism analysis shows that the AlO2-terminated interface enhances the polarization of Ni atom, and the LaO-OT interface has a little influence on the polarization of Ni atom, while the LaO-MT interface reduces the polarization of Ni atom. The LaO-terminated interface is more stable than the AlO2-terminated interface when Delta mu(Ai) is low. While the AlO2-terminated interface becomes more stable when Am is high. When Delta mu(Ai) is less than 14.15 eV and -11.74 eV, the interfacial energy of the LaO-MT interface and LaO-OT interface is smaller than the liquid/solid interfacial energy of Ni (sigma Ni(l)/Ni(s))Ni(s)). When Delta mu(Ai) is more than -9.09 eV and -6.63 eV, the interfacial energy of the AlO2-O-OT and AlO2-Al-OT interfaces is smaller than sigma Ni(l)/Ni(s). Therefore, LaAlO3 can be the heterogeneous nucleus of Ni and refine Ni grains. (C) 2016 Elsevier Ltd. All rights reserved.