The dynamic properties of liquid phase-change materials (PCMs), such as viscosity $\eta$ and atomic self-diffusion coefficients $D$, play an essential role in ultrafast phase switching behavior of novel non-volatile phase-change memory applications. To connect $\eta$ to D, the Stokes-Einstein relation (SER) is commonly assumed to be valid at high temperatures near or above the melting...
Interesting candidates to fulfill the requirement of higher specific energy in Li-ion batteries are Si/C composite anodes. We investigated the charging mechanisms in commercial 18650 cells (anode: graphite + 3% Si, cathode: NCA)1 via operando neutron diffraction with the STRESS-SPEC instrument at the neutron source FRM II in Garching.
Although the amorphous Si compound did not allow following...
ABSTRACT For Ni-Mn-Ga ferromagnetic shape memory alloys, the martensitic transformation produces lattice strain. Appling external deformation during the transformation imposes specific constraints to the lattice deformation thus may change the strain path of the phase transformation. To elucidate such changes, we performed in-situ neutron diffraction inspection on the Ni50Mn30Ga20 samples...
The phase transition kinetics in austempered ductile iron (ADI) and perferritic ductile iron (IDI) are investigated by means of neutron diffraction and dilatometry at the STRESS-SPEC instrument. Measurements with the new TA Instruments 805 A/D quenching dilatometer characterize in-situ the transition from austenite to ferrite. The short instrumental setup description is followed by a...
Co-Re-based alloys [1] are being developed to supplement single crystal Ni-based superalloys in future gas turbines. Higher operation temperatures are foreseen for them enabling a higher efficiency of energy conversion and thus lower fuel consumption. Alloying elements with various functionality are added to these alloys, for example Re to increase melting temperature, Cr or Ni for oxidation...
Cultural heritage made of iron is easily damaged by post excavation corrosion, caused by chloride ions diffusing into the finds during their burial in the soil. Therefore, the chlorine has to be eliminated by conservation treatment, for example by washing the objects in alkaline solutions.
The research project “Besonderes Eise(r)n bewahren” (funded by DBU) is designed for comparison of...
Rotors and stators made from electrical steel are core elements of electric machines. Typically, these are built up of thin shear cut lamellae. However, due to the cutting process, residual stress is introduced into the lamellae and it was found that this detrimentally alters the magnetic properties of the material. The magnetic properties of electrical steels are related to their domain...
In the development of non-conventional solar cells not only the achievements of highest power conversion efficiencies and maximum lifetime of devices is of interest. Also the sustainability of the production process of the devices comes into focus. Following this idea, we developed hybrid solar cells with an active layer based on low temperature processed titania and a water-soluble...
NECTAR is a superior beam-line with access to fission neutrons for non-destructive inspection of large and dense objects, where thermal neutrons or X-rays face limitations due to their comparatively low penetration. With the production of fission neutrons at the instrument, as well as neutrons interacting with beamline geometry, such as the collimator, gamma rays are produced in the process....
Neutron radiography was used in several measurement series at the ANTARES instrument of the FRM2 to characterize influences on the filling process in lithium ion cell production. The filling of the cells with electrolyte liquid consisting of iterative dosing and wetting steps is very time-consuming and has a high influence on the cost and quality of the cells. Since it is otherwise not...
Commonly, smartphones contain about 30 different metals [1]. From these many are considered as Critical Raw Materials (CRMs), as they are economically very important combined with high supply risks and a lack of viable substitutes [2,3]. Therefore, they are critical for a sustainable economy [3]. Additionally, most of these elements are mined under devastating social and/or ecological...
Residual stresses (RSes) in metal matrix composites (MMCs) are more complicated than in homogeneous materials. They can be divided into macro and micro (elastic mismatch, thermal misfit and plastic misfit) RSes. Therefore, precise characterization of RSes in MMCs is difficult. Previous method for diffraction-based RS analysis in MMCs has several drawbacks [1-3].
In the past few years, a new...
In this study the influence of an established electrode-separator lamination technique on the formation of solid-electrolyte-interface (SEI) in graphite anodes is investigated. As we have shown previously, the lamination technique is beneficial for the capacity aging in graphite/LiNi1/3Mn1/3Co1/3O2 (NMC) cells. Here, the non-destructive and highly...
The main aim of this work is to reveal the structure of the layers formed
at the interface between deep eutectic solvents (DES) and silicon sur-
face with and without applied constant electric potential using neutron
reflectometry (NR) and molecular dynamics simulations (MDs). Work
is focused on finding experimental evidence for an ordered layer of DES
over an Si substrate under DC conditions...
