The demand for light-weight, sustainable and high-performance materials is increasing exponentially. Fiber reinforced polymers offer higher strength-to-weight and stiffness-to-weight ratios than traditional materials such as steel, which allows for energy savings and carbon emission reductions. However, their heterogeneous and anisotropic nature makes their behavior far more complex than these traditional materials. In order to analyze their unique and complex damage mechanisms, non-destructive evaluation techniques such as micro-CT are used, but these suffer from poor contrast between the carbon fibers and the polymer matrix. Better visualization of the composite allows for automatic extraction of geometry and damage features to construct accurate damage propagation models. The contrast in X-ray CT is a function of material density and atomic composition. This makes the chemically inert and biocompatible hafnium oxide (HfO2) an excellent contrast agent due to its high density and the high atomic number of Hf. So far there is no affordable synthesis of 5 - 50 nm HfO2 NCs with tunable surface chemistry. This interdisciplinary research aims to upscale the HfO2 NC synthesis and tune the surface for optimal stability in the polymer matrix. These will be used to make nanocomposites and evaluated with micro-CT. The influence on the mechanical properties will also be assessed.