A novel and simple approach for characterizing the Young's modulus of single particles in a soft matrix by nanoindentation

With regard to the micromechanical characterization of particle-matrix composites like Li-ion electrode materials, we utilized nanoindentation technique as a method for quantifying the Young's modulus of a single ceramic particle with a diameter of a few micrometers, which was embedded in a softer polymeric matrix. For the experiments, we used reference composites having high Young's modulus and high hardness ratios of up to 100 (particle/matrix) and filler contents of 10 and 80 vol%. We further performed finite element simulations to understand the indentation process of single particles. It was found that depending on filler content, particle size, and particle/matrix properties, a significant error up to 75% may occur when characterizing single particles by nanoindentation. We finally propose a framework by using standard nanoindentation methods with conventional data analysis as well as an additional postprocess evaluation to determine the Young's modulus of single particles and we discuss its limitations.