From Nanopores to Macropores: Fractal Morphology of Graphite

TL;DR

This study provides a detailed multiscale analysis of nuclear graphite's fractal structure, revealing consistent fractal dimensions across nanometer to millimeter scales using advanced neutron techniques.

Contribution

It introduces a comprehensive methodology combining multiple neutron scattering and imaging techniques to characterize graphite's fractal morphology across all relevant length scales.

Findings

Fractal structure extends from 0.6 nm to 0.6 mm.

Surface and mass fractal dimensions are approximately 2.5.

Fractal morphology is consistent across different length scales.

Abstract

We present a comprehensive structural characterization of two different highly pure nuclear graphites that compasses all relevant length scales from nanometers to sub-mm. This has been achieved by combining several experiments and neutron techniques: Small Angle Neutron Scattering (SANS), high-resolution Spin Echo SANS (SESANS) and neutron imaging. In this way it is possible to probe an extraordinary broad range of 6 orders of magnitude in length from microscopic to macroscopic length scales. The results reveal a fractal structure that extends from $ \sim $ 0.6 nm to 0.6 mm and has surface and mass fractal dimensions both very close to 2.5, a value found for percolating clusters and fractured ranked surfaces in 3D.