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Michael Stueber

Bio: Michael Stueber is an academic researcher from Karlsruhe Institute of Technology. The author has contributed to research in topics: Thin film & Sputter deposition. The author has an hindex of 13, co-authored 27 publications receiving 816 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a review of the latest developments in hard, wear-resistant thin films based on the multilayer coating concept is presented, covering various phenomena such as the superlattice effect, stabilization of materials in another, foreign structure, and effects related to coherent and epitaxial growth.

260 citations

Journal ArticleDOI
TL;DR: In this article, surface modified zirconium (Zr)-based alloys, mainly by fabricating protective coatings, are developed and evaluated as accident-tolerant fuel (ATF) claddings, aiming to improve fuel reliability and safety during normal operations, anticipated operational occurrences, and accident scenarios in water-cooled reactors.
Abstract: Abstract Surface-modified zirconium (Zr)-based alloys, mainly by fabricating protective coatings, are being developed and evaluated as accident-tolerant fuel (ATF) claddings, aiming to improve fuel reliability and safety during normal operations, anticipated operational occurrences, and accident scenarios in water-cooled reactors. In this overview, the performance of Zr alloy claddings under normal and accident conditions is first briefly summarized. In evaluating previous studies, various coating concepts are highlighted based on coating materials, focusing on their performance in autoclave hydrothermal corrosion tests and high-temperature steam oxidation tests. The challenges for the utilization of coatings, including materials selection, deposition technology, and stability under various situations, are discussed to provide some valuable guidance to future research activities.

252 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the performance of single-phase and dense Ti 2 AlC/TiC coatings with or without a 500-nm diffusion barrier on Zircaloy-4 by annealing of nanoscale multilayer stacks between 800 and 1200°C in high-temperature steam.

70 citations

Journal ArticleDOI
TL;DR: In this paper, a series of (Ti,Al)(N,C) coatings with different carbon contents (0-28 at.%) have been deposited by reactive magnetron sputtering of TiAl in a mixture of Ar, N-2 and CH4 gases.

62 citations

Journal ArticleDOI
TL;DR: In this paper, a combinatorial experimental approach was chosen to describe the growth and microstructure evolution of Al-Cr-O thin films by means of reactive r.f. magnetron sputtering.
Abstract: The development of new coatings with superior functionalities for high performance cutting tools is a key challenge in manufacturing. In this context, the synthesis of aluminium oxide and derivative oxide thin films is attracting large scientific and technical interests. The present paper addresses fundamental materials science-based aspects of the physical vapour deposition (PVD) growth of Al–Cr–O thin films at a substrate temperature of 500 °C. A combinatorial experimental approach was chosen to describe the growth and microstructure evolution of Al–Cr–O thin films by means of reactive r.f. magnetron sputtering. A segmented target consisting of two half plates of Al and Cr was used for the deposition carried out under stationary conditions in a laboratory-scale PVD coater. Opposite to the cathode five substrate samples were placed in a line. The r.f. cathode power was set to 500 W and the r.f. substrate bias was set to − 100 V. The total gas pressure was kept constant at 0.4 Pa for all experiments with a fixed ratio of oxygen to argon gas flow. Detailed results on the coatings composition, constitution, microstructure and properties as a function of the elemental composition are presented. X-Ray Diffraction (XRD), X-Ray Reflection (XRR), Transmission Electron Microscopy (TEM) and Electron Probe Microanalysis (EPMA) studies prove the growth of nanocrystalline, stoichiometric, metastable corundum-like solid solution strengthened α-(Al 1 − x ,Cr x ) 2 O 3 thin films with a high degree of crystallinity, grain sizes between 27 ± 6 nm (in the case of Al-rich coatings) and 44 ± 17 nm (in the case of Cr-rich coatings), Vickers micro hardness values up to 2620 ± 80 HV0.05 and thin film densities between 4.00 g/cm³ (in the case of Al-rich coatings) and 4.86 g/cm³ (in the case of Cr-rich coatings).

59 citations


Cited by
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Journal ArticleDOI
TL;DR: The components of the macroscopic mechanical stress tensor of a stressed thin film, coating, multilayer or the region near the surface of a bulk material can in principle be determined by X-ray diffraction as discussed by the authors.
Abstract: The components of the macroscopic mechanical stress tensor of a stressed thin film, coating, multilayer or the region near the surface of a bulk material can in principle be determined by X-ray diffraction. The various analysis methods and measurement strategies, in dependence on specimen and measurement conditions, are summarized and evaluated in this paper. First, different X-ray diffraction geometries (conventional or grazing incidence) are described. Then, the case of macroscopically elastically isotropic, untextured specimens is considered: from the simplest case of a uniaxial state of stress to the most complicated case of a triaxial state of stress. The treatment is organized according to the number of unknowns to be determined (i.e. the state of stress, principal axes known or unknown), the use of one or several values of the rotation angle φ and the tilt angle ψ of the sample, and one or multiple hkl reflections. Next, the focus is on macroscopically elastically anisotropic (e.g. textured) specimens. In this case, the use of diffraction (X-ray) elastic constants is not possible. Instead, diffraction (X-ray) stress factors have to be used. On the basis of examples, it is demonstrated that successful diffraction stress analysis is only possible if an appropriate grain-interaction model is applied.

529 citations

Journal ArticleDOI
TL;DR: A review of the development status for three accident tolerant fuel cladding technologies, namely coated zirconium-based cladding, ferritic alumina-forming alloy cladding and silicon carbide fiber-reinforced SCCM composite, is offered in this paper.

494 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the latest developments in hard, wear-resistant thin films based on the multilayer coating concept is presented, covering various phenomena such as the superlattice effect, stabilization of materials in another, foreign structure, and effects related to coherent and epitaxial growth.

260 citations

Journal ArticleDOI
TL;DR: In this paper, the challenges of instrumented micro-and nanomechanical testing at elevated temperature are summarized and a special focus is laid on the pitfalls of micro-compression testing with its stringent boundary conditions often hampering reliable experiments.

260 citations

Journal ArticleDOI
TL;DR: In this article, surface modified zirconium (Zr)-based alloys, mainly by fabricating protective coatings, are developed and evaluated as accident-tolerant fuel (ATF) claddings, aiming to improve fuel reliability and safety during normal operations, anticipated operational occurrences, and accident scenarios in water-cooled reactors.
Abstract: Abstract Surface-modified zirconium (Zr)-based alloys, mainly by fabricating protective coatings, are being developed and evaluated as accident-tolerant fuel (ATF) claddings, aiming to improve fuel reliability and safety during normal operations, anticipated operational occurrences, and accident scenarios in water-cooled reactors. In this overview, the performance of Zr alloy claddings under normal and accident conditions is first briefly summarized. In evaluating previous studies, various coating concepts are highlighted based on coating materials, focusing on their performance in autoclave hydrothermal corrosion tests and high-temperature steam oxidation tests. The challenges for the utilization of coatings, including materials selection, deposition technology, and stability under various situations, are discussed to provide some valuable guidance to future research activities.

252 citations