Schroeder Joan Widin, Burch Matthew J, Perez Mario A
3M Company, St. Paul, MN, USA.
3M Company, St. Paul, MN, USA.
Micron. 2024 Jan;176:103556. doi: 10.1016/j.micron.2023.103556. Epub 2023 Oct 13.
Complex morphologies, such as open or connected feature networks, are present in a wide variety of materials. Characteristics of these networks can impact key performance attributes of the materials themselves, affecting transport properties such as thermal conductivity. Therefore, it is critical to analyze the microstructure of these materials to gain a better understanding of the fundamental characteristics of the morphology. This study utilized pore network modeling as a method to extract morphological information on the solid network formed by boron nitride ceramic flakes in a polymeric resin matrix and uses the characteristics of the model to analyze the connectivity of the flakes. In this work, Micro-CT and FIB/SEM tomography were used in tandem to provide complimentary analyses of the microstructure and nanostructure, respectively, of the flake network to understand how this may contribute to transport properties of the material. Rather than a pore network model (PNM), the flake network model (FNM) was extracted from the tomographic datasets and the coordination number distribution was determined for the flakes detected in each. Micro-CT analysis showed that the flakes had formed a cage-like network around the exterior of the sample with limited connectivity in the interior, likely due to flake agglomeration at the outer surface of the material. A comparison of the full and interior-only Micro-CT FNMs indicated lower connectivity in the interior. This was confirmed by flow rate models generated from the network analysis for the flake contact points. The FNM extracted from the FIB/SEM tomography dataset exhibited similar connectivity compared to the interior-only FNM, indicating that the connectivity of the material was consistent when measured at the micron scale and at the nanometer scale.
复杂的形态，如开放或连通的特征网络，存在于各种各样的材料中。这些网络的特性会影响材料本身的关键性能属性，进而影响诸如热导率等传输特性。因此，分析这些材料的微观结构对于更好地理解形态的基本特征至关重要。本研究利用孔隙网络建模作为一种方法，来提取聚合物树脂基体中氮化硼陶瓷薄片形成的固体网络的形态信息，并利用该模型的特性分析薄片的连通性。在这项工作中，微型计算机断层扫描（Micro-CT）和聚焦离子束/扫描电子显微镜断层扫描（FIB/SEM）被串联使用，分别对薄片网络的微观结构和纳米结构进行补充分析，以了解这如何影响材料的传输特性。从断层扫描数据集中提取的不是孔隙网络模型（PNM），而是薄片网络模型（FNM），并确定了在每个模型中检测到的薄片的配位数分布。微型计算机断层扫描分析表明，薄片在样品外部形成了笼状网络，内部连通性有限，这可能是由于材料外表面的薄片团聚所致。对完整的和仅内部的微型计算机断层扫描薄片网络模型的比较表明，内部的连通性较低。这通过对薄片接触点的网络分析生成的流速模型得到了证实。从聚焦离子束/扫描电子显微镜断层扫描数据集中提取的薄片网络模型与仅内部的薄片网络模型相比，显示出相似的连通性，表明在微米尺度和纳米尺度测量时，材料的连通性是一致的。
