Correlative X-ray and electron tomography for scale-bridging, quantitative analysis of complex, hierarchical particle systems

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This study presents a comprehensive workflow for investigating particulate materials through combined 360° electron tomography (ET), nano-computed X-ray tomography (nanoCT), and micro-computed X-ray tomography (microCT), alongside a versatile sample preparation routine. The workflow enables the investigation of size, morphology, and pore systems across multiple scales, from individual particles to large hierarchical structures. A customized tapered sample shape is created using focused ion beam milling to optimize the field of view for each imaging technique. This design enables high-resolution analysis of small volumes containing single particles using nanoCT and large-scale studies of thousands of particles for statistical significance using microCT. By correlating data from identical locations across different microCT and nanoCT imaging modalities - without any additional preparation that could affect the sample in between - the presented approach improves the precision of quantitative analyses. The study highlights the importance of cross-scale, correlative three-dimensional microscopy for a comprehensive understanding of complex hierarchical materials. Precise data registration, segmentation using machine learning, and multimodal imaging techniques are crucial for unlocking insights into process-structure-property relationships and thus to optimize functional, hierarchical materials.