关键词: 二氧化钛, 纳米粒子, 烧结, 分子动力学模拟, 扩散

Abstract:

Chlorinated titanium dioxide is an important inorganic raw material for chemical industry and energy storage, and its properties are controlled by multiple factors such as sintering heat treatment. Traditional experimental methods are difficult to accurately quantify and analyze the sintering process, and molecular dynamics simulations can accurately assess the dynamic evolution of sintering from the atomic scale, but the existing studies are relatively single-limit for the mechanistic interpretation of factors such as temperature, particle size and arrangement. A non-isotropic multi-particle model and effective characterization parameters such as sintering neck size, Lindemann index and apparent activation energy were introduced, and the effects of temperature, particle size and arrangement on the sintering behavior of TiO₂ nanoparticles were investigated by molecular dynamics simulation system. The results showed that increasing the temperature was conducive to stimulating intense atomic migration and diffusion and accelerating the densification process of the sintered body. When the temperature was the same, the sintering rate of TiO₂ nanoparticles with smaller particle size was faster, but it was easy to be absorbed and fused by the particles with larger particle size. In addition, the particle arrangement also affected the sintering behavior with the stacked arrangement having a more obvious sintering advantage than the linear arrangement. The initial stage of sintering was mainly through surface diffusion growth, while the later stage was through grain boundary diffusion densification. The results were of guiding significance for optimizing industrial sintering parameters and preparing high-performance nanomaterials.

Key words: titanium dioxide, nanoparticles, sintering, molecular dynamics simulation, diffusion