Multi-Scale Study of Nanoparticle Sintering

该基金通过量化不同纳米颗粒填料的三维（3D）结构演变并将微观结构特征与宏观收缩联系起来，为多尺度纳米颗粒烧结研究提供资金。要解决的主要问题是颗粒团聚，过度晶粒生长，复杂的纳米/微米结构演变，和不均匀的收缩。烧结是一种高温过程，其中颗粒，在这种情况下是纳米颗粒（直径小于100微米），被固结成固体形式。该过程涉及从原子扩散到宏观收缩的多尺度事件，并创建长期使用的稳定纳米结构。将进行实验以在所有尺度上产生均匀和团聚的二氧化钛和二氧化锆纳米颗粒填充结构。所得的纳米结构将定量描述和相关的晶粒生长和宏观收缩，通过纳米结构的电子断层扫描和聚焦离子束3D渲染。如果成功的话，这项研究的结果将为纳米颗粒烧结中的关键问题提供理解。这些包括不同的纳米颗粒填充，过度的晶粒生长，复杂的纳米/微米结构的演变，和不均匀的收缩的影响。 该团队将开发在整个烧结过程中将纳米/微观结构演变和宏观致密化联系起来的理论。跨多尺度的综合理解将提供全面的烧结知识，并使该领域能够挑战迄今为止公认的烧结理论和观点。通过适当的调整，该方法和突破也可以应用于具有众多应用的常规微米级颗粒烧结。该计划产生的新理论指导烧结工艺也将允许更节能的烧结实践。该研究方法在提高工艺可靠性和可制造性的同时，对多尺度器件集成具有广泛的意义。

This grant provides funding for a nanoparticle sintering study across multi-scales through quantifying three-dimensional (3D) structural evolution of different nanoparticle packings and connecting the microstructural characteristics with macroscopic shrinkage. The primary issues to be addressed are particle agglomeration, excessive grain growth, complex nano-/micro-structural evolution, and non-uniform shrinkage. Sintering is a high temperature process whereby particles, in this case nanoparticles (with diameters less than 100 micrometers), are consolidated into solid form. The process involves multi-scale events that range from atomic diffusion to macroscopic shrinkage and creates stable nanostructures for long term use. Experiments will be carried out to create homogeneous and agglomerated titanium dioxide and zirconium dioxide nanoparticle packing structures across all scales. The resulting nanostructure will be quantitatively described and correlated with grain growth and macroscopic shrinkage through nanostructural electron tomography and focused ion beam 3D rendering. If successful, the results of this research will provide understanding to the key issues in nanoparticle sintering. These include the effects of different nanoparticle packings, excessive grain growth, complex nano-/micro-structural evolution, and non-uniform shrinkage. The team will develop theories that link nano-/micro-structural evolution and macroscopic densification throughout the entire sintering process. The integrated understanding across multi-scales will provide comprehensive sintering knowledge and enable the field to challenge the heretofore-accepted sintering theories and perspectives. With proper adjustment, the methodology and breakthrough can also be applied to conventional micron-sized particle sintering which has numerous applications. New theory-guided sintering processes resulting from this program will also allow for more energy efficient sintering practices. The research methodology has wide-ranging significance in multi-scale device integration while improving process reliability and manufacturability.