Micro-computed tomography (CT) is an X-ray tomography technique with (sub)micron resolution, typically using an X-ray tube with cone-beam geometry as a source and a rotating sample holder. While conventional CT maintained a strong position in life science and low-resolution high-energy CT became widespread in industrial quality control, micro-CT has enjoyed a boost in interest from the materials science research community in the past decade. The key reasons behind this are the versatile, non-destructive nature of micro-CT as a characterization method offering also in situ and in operando possibilities and the fact that micro-CT has become indispensable in developing and verifying computational material models as well. The goal of the present mini review is to give a concise introduction of the method to newcomers and showcase a few impressive recent results that can help in devising even more innovative future uses of micro-CT. After a brief overview of alternative three-dimensional imaging techniques, we review the basics of micro-CT covering important concepts such as resolution, magnification, and the Hounsfield unit. The second part of the article summarizes characteristic materials science micro-CT applications in bioinspired materials, structural materials, porous natural materials, energy storage, energy conversion, and filtration.
