Porosity Mapping in Fiber-Reinforced Ceramics with A Multiscale 3D Imaging Approach from Micro to Nano

Why Porosity Needs to Be Characterized at Multiple Scales

In materials like HA-ZrO₂ composites, pores are neither uniform in size nor evenly distributed. Single-method workflows, whether based on micro-CT, FIB-SEM, or other techniques, each come with inherent trade-offs between resolution and volume. As a result, critical information may be missed when relying on only one method.

Macroporosity may be visible in large-volume scans, but fine-scale porosity at the fiber–matrix interface often escapes detection. Without complete information, correlations between structure and function become unreliable — a gap this workflow aims to close.

Multiscale Imaging Workflow for Accurate Porosity Mapping

The composite studied was fabricated using electrophoretic deposition and included randomly oriented zirconia fibers within a hydroxyapatite matrix. Imaging began with micro-CT, providing a non-destructive view of internal structure and guided the laser ablation process.

Laser ablation enabled fast and site-specific access to regions of interest for higher-resolution imaging with TESCAN AMBER X, a plasma FIB-SEM system.3D tomography was used to capture porosity distribution and fiber architecture in three dimensions.

Nano-CT imaging revealed porosity clusters and structural defects that fell into the size range not well resolved by micro-CT or FIB-SEM, demonstrating its role as an intermediate-scale technique bridging the gap between the two.

Correlated Insights from Micro to Nano Porosity

Micro-CT showed macroscopic pore networks and highlighted inhomogeneous phase distribution. Laser ablation ensured efficient targeting of areas for deeper analysis and sped up the process of sample preparation.   FIB-SEM tomography enabled nanoscale 3D visualization of the smallest pores within the composite structure.   Nano-CT provided high-resolution volume data, revealing porosity features too small to be resolved with microCT and too large to be analysed with FIB-SEM alone.

Together, these datasets revealed a random but critical distribution of pore sizes — from sub-micron voids to multi-micron still pores  —   demonstrating how multiscale imaging captures the full porosity landscape. The integrated data confirmed that material fabrication processes   directly influence internal porosity patterns, a relationship not visible with single-method imaging.