EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

In-situ 3D imaging has proved to be highly valuable for improving the understanding and modeling of sintering of metallic and glass powders. For ceramics, owing to the complex and fine architecture of the individual grains, a much better resolution is required. Hence the experimental studies conducted previously on ceramic sintering have mostly been concerned with agglomerates, rather than at the length-scale of particles. This can now be dealt by taking advantage of the outstanding features of the upgraded ESRF synchrotron. The resolutions and the scan times available at the ID16B beamline at ESRF were used to perform nanotomography analyses of both free and constrained sintering mechanisms for several representative ceramic powder systems. A high temperature furnace was designed and fabricated for the same. A non-agglomerated alumina powder mixed with different volume fractions of inert inclusions, allowing for the application of different constraints, and an agglomerated powder composed of sub-micronic zinc oxide particles were sintered at 1500°C and 1000°C respectively. Complete 3D images were obtained with a voxel size below 100 nm, so as to depict particles and pores with enough details for quantitative analysis; and with a fast and continuous acquisition, so as to limit the changes between two successive images and follow the full sintering process. Data resulting from quantitative image analysis were used to explore densification and grain growth both with and without the presence of inclusions throughout the sintering cycle.