Strukturbildungsdynamik von Legierungsnanopartikel-Filamenten in makroskopischen Polymerkompositen
Zusammenfassung der Projektergebnisse
The goal of the present project has been to understand the laser-based nanoalloy formation and resolve the structural dynamics of magnetic nanoalloy filaments in macroscopic polymer composites using experiments and simulations, correlating the formation of nanoparticle filaments with physical properties and material parameters such as viscosity, magnetic field strength, nanoparticle size, and magnetic moment. Methodically this required an increase in nanoparticle productivity and minimization of oxidation in the pulsed laser ablation in liquid process. Furthermore, a simulation room for the study of the nanoparticle-filament formation had to be constructed. Simulation was performed by the finite element software COMSOL Multiphysics while experimental validation was achieved by optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscope (TEM). Several milestone results have been accomplished that drew considerable attention in the scientific community: • Synthesis and characterization of iron-based alloy nanoparticles with variable composition, such as FeNi, FeAu, FeRh and high entropy alloys (Cantor alloys). • Increase in nanoparticle productivity by identifying laser induced surface structures during laser synthesis and their cancellation. • Three main factors for oxidation of nanoalloys were identified and analyzed: (1) dissolved oxygen in the utilized organic solvents, (2) the bound oxygen in the solvent, and (3) oxygen in the atmosphere above the solvent. Through optimization, it was shown that oxidation can be significantly reduced in pulsed laser ablation in liquids. • Synthesis of equimolar FeRh nanoparticles by laser ablation process for ink development for laser sintering process. Quenched phases could be recovered by heating or further irradiation with a continuous wave laser. • Magnetic field-induced strand formation of ferromagnetic FeNi nanoparticles in a PMMA matrix could be correlated with intrinsic material parameters, such as magnetization, particle size, composition, and extrinsic parameters, including magnetic field strength and viscosity. For this purpose, a finite element simulation model could be developed for the prediction of strand formation.
Projektbezogene Publikationen (Auswahl)
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Kinetically-controlled laser-synthesis of colloidal high-entropy alloy nanoparticles. RSC Advances 2019, 9, 18547-18558
Waag, F.; Li, Y.; Ziefuß, A.R.; Bertin, E.; Kamp, M.; Duppel, V.; Marzun, G.; Kienle, L.; Barcikowski, S.; Gökce, B.
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Controlling the Oxidation of Magnetic and Electrically Conductive Solid-Solution Iron-Rhodium Nanoparticles Synthesized by Laser Ablation in Liquids. Nanomaterials 2020, 10
Nadarajah, R.; Tahir, S.; Landers, J.; Koch, D.; Semisalova, A.S.; Wiemeler, J.; El- Zoka, A.; Kim, S.H.; Utzat, D.; Moller, R.; Gault, B.; Wende, H.; Farle, M.; Gökce, B.
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Picosecond laser-induced surface structures on alloys in liquids and their influence on nanoparticle productivity during laser ablation. Optics Express 2020, 28, 2909-2924
Nadarajah, R.; Barcikowski, S.; Gökce, B.
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Formation of Fe-Ni Nanoparticle Strands in Macroscopic Polymer Composites: Experiment and Simulation. Nanomaterials 2021, 11
Nadarajah, R.; Tasdemir, L.; Thiel, C.; Salamon, S.; Semisalova, A.S.; Wende, H.; Farle, M.; Barcikowski, S.; Erni, D.; Gökce, B.
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Towards laser printing of magnetocaloric structures by inducing a magnetic phase transition in ironrhodium nanoparticles. Scientific Reports 2021, 11, 13719
Nadarajah, R.; Landers, J.; Salamon, S.; Koch, D.; Tahir, S.; Donate-Buendia, C.; Zingsem, B.; Dunin-Borkowski, R.E.; Donner, W.; Farle, M.; Wende, H.; Gökce, B.
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Towards synthetic L10-FeNi: Detecting the absence of cubic symmetry in Laser-Ablated Fe-Ni nanoparticles. Applied Surface Science 2021, 567
Lin, Q.; Nadarajah, R.; Hoglund, E.; Semisalova, A.; Howe, J.M.; Gökce, B.; Zangari, G.
