Porosity and Void Size Quantification in Carbon Materials with X-ray-Computed Tomography (XCT) and Mercury Infiltration Porosimetry (MIP)

Author(s):

Jennifer M Sietins, Ngon T Tran, Daniel B Knorr Jr, Jason J Cain, and Keaton W Klaff

Abstract:

Porosity quantification is a critical measurement for accurately determining material density and processing–microstructure performance relationships. X-ray-computed tomography (XCT) and mercury infiltration porosimetry are complementary techniques that can be used to obtain a big picture of the internal void structure and progression at varied processing stages. However, each technique has its limitations, which will be discussed in detail within this report. Both glassy carbon foams and a 3-D carbon weave were used to study the instrument capabilities and measurement ranges. Percent porosity, bulk densities, and skeletal densities were directly compared, and explanations provided for discrepancies between them. Additionally, void sizes and location dependencies were quantified for XCT. This information can be used to discern which techniques would be better suited for specific samples of interest based on the expected void size range and, more importantly, to understand the accuracy limitations of the different methods.