A method to approach constant isotropic permeabilities and demagnetization factors of magneto-rheological elastomers. - In: Journal of magnetism and magnetic materials, ISSN 1873-4766, Bd. 527 (2021), 167742
The use of non-conventional materials is nowadays of much interest in scientific community. Magneto-rheological elastomers are hybrid materials, which in presence of magnetic fields state a change in their mechanical properties. They are composed by an elastomeric matrix with embedded magnetic particles. One of the most attractive features of these materials is that as soon as the magnetic field is removed from the material, the original mechanical properties are completely recovered, with negligible differences in comparison to the original state. This paper focuses on the study of magnetic characteristics of these smart materials, such as relative permeability and demagnetizing factors, for samples with different volume concentration of ferromagnetic particles.
https://doi.org/10.1016/j.jmmm.2021.167742
Photo-thermoelectric conversion using black silicon with enhanced light trapping performance far beyond the band edge absorption. - In: ACS applied materials & interfaces, ISSN 1944-8252, Bd. 13 (2021), 1, S. 1818-1826
https://doi.org/10.1021/acsami.0c17279
Effect of thermoplastic morphology on mechanical properties in laser-assisted joining of polyamide 6 with aluminum. - In: Welding in the world, ISSN 1878-6669, Bd. 65 (2021), 4, S. 699-711
This paper examined the joining zone between semi-crystalline polyamide 6 and aluminum EN AW 6082 in laser-based joining and evaluated the mechanical properties of the joint. The joint tests were carried out in overlap configuration and a characterized in terms of energy per unit length. The mechanical properties were examined to the point of cohesive failure. An increasing energy per unit length resulted in a reduced crosshead displacement in short-term testing and a decreased fatigue strength. Further material testing was carried out locally at various positions within the joining zone. The mechanical properties were correlated with results of a hardness test, thermoplastic morphology, differential scanning calorimetry (DSC), and X-ray diffraction (XRD). By combining the findings with heat-treated samples at elevated temperatures, secondary crystallization was identified and evidenced as a primary effect among the changes in mechanical properties due to the heat treatment of the thermoplastic material.
https://doi.org/10.1007/s40194-020-01048-1
Method for contact resistance determination of copper during fast temperature changes. - In: Journal of materials science, ISSN 1573-4803, Bd. 56 (2021), 5, S. 3827-3845
https://doi.org/10.1007/s10853-020-05490-w
Formation of CuCrCoFeNiO high entropy alloy thin films by rapid thermal processing of Cu/CrNiO/FeCo multilayers. - In: Surface and coatings technology, ISSN 1879-3347, Bd. 405 (2021), 126563
https://doi.org/10.1016/j.surfcoat.2020.126563
Development of the phase composition and the properties of Ti2AlC and Ti3AlC2 MAX-phase thin films - A multilayer approach towards high phase purity. - In: Applied surface science, Bd. 537 (2021), 147864
MAX phase thin films have been synthesized by thermal treatment of a Ti-Al-C multilayer system. The preparation of the multilayer system was carried out via magnetron sputtering. Based on the thickness ratio among the individual nanoscale monolayers (Ti, Al, C), the resulting MAX phase stoichiometry can be controlled. This paper describes the synthesis of both Ti2AlC and Ti3AlC2 MAX phases from the same precursor multilayer system which is composed of a sequence of Ti/Al/C pure elemental single layers with thicknesses of 14, 6, and 3.5 nm, respectively. This sequence is repeated 22 times with a total thickness of around 500 nm. Rapid thermal treatment tests were performed to study the phase development. The Ti2AlC MAX phase forms in a temperature range below 850 ˚C, whereas the Ti3AlC2 MAX phase starts to form at temperatures above 850 ˚C and reaches its highest phase purity at 950 ˚C. The thin film structures were studied by X-ray diffraction and Raman spectroscopy. Furthermore, the electrical and mechanical properties were investigated to gain more insights regarding the phase transformation and their influence on the thin film properties.
https://doi.org/10.1016/j.apsusc.2020.147864
Synthesis and characterization of size controlled bimetallic nanosponges. - In: Multifunctional materials, (2020), S. 1-34
Metallic and bimetallic nanosponges with well-defined size and form have attracted increasing attention due to their unique structural properties and their potential for many applications. In this chapter, the recently developed methods for the synthesis and preparation of metallic and bimetallic nanosponges are presented. These methods can be mainly cataloged in two groups: dealloying-based methods and reduction reaction-based methods. Different topographical reconstruction methods for the investigation of their structural properties are then reviewed briefly. The optical properties of the metallic nanosponges are clearly different from those of the solid counterparts due to the tailored disordered structure. The recent advances in the exploration of the distinct linear and non-linear optical properties of the nanosponges are summarized.
https://doi.org/10.1515/9783110345001-001
Multiferroic bismuth ferrite: perturbed angular correlation studies on its ferroic α-β phase transition. - In: Physical review, ISSN 2469-9969, Bd. 102 (2020), 22, S. 224110-1-224110-11
https://doi.org/10.1103/PhysRevB.102.224110
Metastable atomic layer deposition: 3D self-assembly toward ultradark materials. - In: ACS nano, ISSN 1936-086X, Bd. 14 (2020), 11, S. 15023-15031
Black body materials are promising candidates to meet future energy demands, as they are able to harvest energy from the total bandwidth of solar radiation. Here, we report on high-absorption near-blackbody-like structures (>98% for a wide solar spectrum range from 220 to 2500 nm) consisting of a silica scaffold and Ag nanoparticles with a layer thickness below 10 m, fabricated using metastable atomic layer deposition (MS-ALD). Several effects contribute collectively and in a synergistic manner to the ultrahigh absorption, including the pronounced heterogeneity of the nanoparticles in size and shape, particle plasmon hybridization, and the trapping of omnidirectionally scattered light in the 3D hierarchical hybrid structures. We propose that, in the future, MS-ALD needs to be considered as a simple and promising method to fabricate blackbody materials with excellent broadband absorption.
https://doi.org/10.1021/acsnano.0c04974
Das physikalische Praktikum : Handbuch 2020/2021 für Studentinnen und Studenten der Physik. - Göttingen : Universitätsverlag Göttingen, 2020. - (Universitätsdrucke)