March 14 2024 at 3 pm at Karolina Lanckorońska Hall in the building of the Polish Academy of Arts and Sciences (PAU) a scientific meeting of the Technical Sciences Committee, Materials Science Section, took place. During the meeting, prof. Robert Filipek (Faculty of Materials Science and Ceramics, AGH) gave a lecture “Transport and reactions in multicomponent porous materials taking into account three-dimensional microstructure – application of high-resolution computed tomography”. The lecture met with interest from the scientific community and followed by a discussion.
Abstract Transport and reactions in porous media are crucial in many fields and practical applications, such as durability of concrete structures, resistance to infiltration, optimization of electrochemical sensors, and design of batteries and fuel cells.
Most transport and reaction models in electrochemistry can be divided into two groups. The first one treats the investigated system as a homogeneous medium in which the transport of many ions and reactions at the electrodes take place. The second approach focuses on mapping the actual microstructure of the investigated material, but then only considers simplified transport models (e.g. one ion and Fickian diffusion). A model based on the theory of coupled mass and charge transport in multi-component concentrated electrolytes will be presented, taking into account the three-dimensional microstructure of the material, which combines both of these approaches.
A new approach to describing the corrosion of reinforcing bars in reinforced concrete will be presented, in which the actual 3D microstructure of concrete is obtained using high-resolution X-ray computed tomography (XCT). It will be demonstrated that multiscale 3D imaging provides significant information about the material microstructure. The XCT experimental data is processed to generate a mesh for finite element method (FEM) calculations and finally combined with a multi-component system of transport and electric potential equations. This methodology allows for a more realistic description of ion transport in concrete and reactions on the surface of reinforcing bars, and, consequently, for a more accurate quantitative description of anodic and cathodic currents on the reinforcement surface and the location of corrosion.
The second example will concern the analysis of the infiltration resistance of microporous carbon materials. A new method will be presented to study the degradation mechanism of multiphase refractory carbon materials in contact with liquid metal by combining advanced 3D modeling with micro-computed tomography. The developed model allows for numerical simulation of the flow of liquid metal in the pores of the material, with a moving infiltration front, combined with the selective dissolution of elements of microporous carbon material in the liquid metal. Such calculations were, for the first time, performed in three-dimensional (3D) geometry representing the microstructure of an actual microporous carbon material.
The third group of examples will concern the use of modeling to optimize the detection limit of ion-selective electrodes used in clinical analysis, electroanalytical chemistry and ion transport in cell membranes.