图2 模拟盒（20 nm×15 nm×15 nm）中两个Fe2O3颗粒（直径D0，初始分隔距离d0 =0.4 nm）

Fig.2 Two Fe2O3 nanoparticles (diameter D0) in a simulation box (20 nm × 15 nm × 15 nm) with an initial separation distance d0 = 0.4 nm

图1 Fe2O3纳米颗粒的建模过程(a)Fe2O3单晶胞;(b)超晶胞;(c)球形切割超晶胞;(d)Fe2O3单颗粒

Fig.1 Modelling process of Fe2O3 nanoparticles(a) Fe2O3 single cell; (b) supercell; (c) spherically cut supercell; (d) Fe2O3 single nanoparticle

图3 烧结颈部区域划分(a)烧结颈;(b)颈部横截面

Fig.3 Sintered neck area division(a) sintered neck; (b) cross section of the neck area

图4 右侧颗粒壳层、中间层及核心层划分

Fig.4 Division of shell, mesosphere and core layer

图6 300 K与1300 K模拟下系统势能变化

Fig.6 The potential energy changes under 300 K and 1300 K simulations

图7 不同温度纳米颗粒烧结过程(a)收缩率;(b)回转半径;(c)颈部宽度;(d)颈部原子数

Fig.7 Sintering process of nanoparticles under different temperatures(a) shrinkage rate; (b) gyration radius; (c) neck width; (d) number of atoms in the neck

图5 300 K及1300 K模拟烧结体结构变化

Fig.5 Structural changes of sintered particles under 300 K and 1300 K simulations

图8 不同粒径纳米颗粒1300 K下烧结体结构变化

Fig.8 Structural changes of sintered nanoparticles with different particle sizes at 1300 K

图9 不同粒径纳米颗粒烧结过程(a) 收缩率; (b) 归一化回转半径; (c) 归一化颈部宽度; (d) 颈部原子数/原子总数

Fig.9 Sintering process of nanoparticles with different particle sizes(a) shrinkage rate; (b) normalized gyration radius; (c) normalized neck width; (d) number of atoms in the neck/total number of atoms

图10 不同温度烧结模拟的原子扩散特性(a)MSD曲线;(b)扩散系数;(c)拟合扩散活化能

Fig.10 Atomic diffusion properties of sintering simulations under different temperatures(a) MSD curves; (b) diffusion coefficient; (c) fitted diffusion activation energy

图11 1300 K烧结模拟中的原子迁移特性(a)原子位移矢量;(b)不同层原子MSD;(c)单颗粒原子位移

Fig.11 Atomic migration properties in 1300 K sintering simulations(a) atomic displacement vectors; (b) MSD of different layers of atoms; (c) single particle atomic displacement

图12 不同温度烧结体的径向分布函数(RDF)

Fig.12 Radial distribution function (RDF) of the sintered nanoparticle under different temperatures

图13 1300 K模拟烧结体的晶体结构演变(a)晶体结构变化(蓝色—BCC结构、红色—HCP结构、黄色—无定形结构);(b)不同结构比例变化

Fig.13 Crystal structure evolution of sintered nanoparticles at 1300 K simulation(a) changes in crystal structure (blue — BCC, red — HCP, yellow — amorphous); (b) changes in proportions of different structures

图15 不同空位浓度纳米颗粒烧结过程(a)收缩率;(b)回转半径;(c)颈部宽度;(c)颈部原子数

Fig.15 Sintering process of nanoparticles with different vacancy concentrations(a) shrinkage rate; (b) gyration radius; (c) neck width; (d) number of atoms in the neck

图16 Cv=10.0% 颗粒不同温度烧结的原子扩散特性(a)MSD曲线;(b)扩散系数;(c) 拟合扩散活化能

Fig.16 Atomic diffusion characteristics of Cv=10.0% nanoparticles sintered under different temperatures(a) MSD curves; (b) diffusion coefficients; (c) fitted diffusion activation energy

图14 不同空位浓度纳米颗粒1300 K下烧结体结构变化

Fig.14 Structural changes of sintered nanoparticles with different vacancy concentration at 1300 K