SYNTHESIS OF METALLIC PARTICLES WITH ANISOTROPIC MORPHOLOGIES VIA SOLIDIFICATION PATH

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SYNTHESIS OF METALLIC PARTICLES.pdf
SYNTHESIS OF METALLIC PARTICLES.pdf

Date

2022-8-12

Author

Ulusel, Mert

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The morphology of alloys is dependant on the kinetics and thermodynamics of solidification. While the relation between these phenomena and the microstructure of bulk alloys is known, their effects on particle morphologies has scarcely been studied. Particles are an exceptional model system for the study of nucleation and solidification phenomena because it is possible to isolate individual nucleants, or obtain systems with far less catalytic sites compared to bulk alloys. This makes it possible to obtain undercooling values orders of magnitude greater in comparison to bulk alloys. Large quantities of such particles can be produced with simple physical methods. The potency and distribution of catalytic sites, while not directly observable, can be modified with large scale treatments on particles, making it possible to control the stochasticity associated with the aforementioned events. Distinct particle morphologies, such as Janus particles, the production of which are nontrivial with bottom up methods, can be produced by this approach. In this thesis, by the modification of the solidification parameters, including thermal history, oxygen content of the environment and cooling rate, particles with Janus, Triblock Janus and other distinct morphologies are produced. While the underlying mechanisms are complex, such particles are consistently obtained in the gram scale. Production of even more complex anisotropic morphologies, and the realisation of applications requiring a large amount of such particles are made possible with a top-down approach to particle design.

Subject Keywords

anisotropic particles, janus particles, solidification of liquid alloys, eutectic bismuth-tin

URI

https://hdl.handle.net/11511/99784

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

M. Ulusel, “SYNTHESIS OF METALLIC PARTICLES WITH ANISOTROPIC MORPHOLOGIES VIA SOLIDIFICATION PATH,” M.S. - Master of Science, Middle East Technical University, 2022.