Search
Now showing items 1-4 of 4
Aufsatz
Linking through-thickness cracks in metallic thin films to in-situ electrical resistance peak broadening
(2022-01-29)
Measurements of electrical resistance have been used extensively as a failure criterion in cyclically loaded conductive films. However, not much research has been performed on extracting additional information contained within such resistance data sets. This study shows that an increase in peak width evidences a transition from cracks bridging to through-thickness crack formation. A Au/Cr bilayer system on a polyimide substrate is used for data generation but the method is applicable to any material system where both ...
Aufsatz
Additive Manufacturing of 3D Luminescent ZrO2:Eu3+ Architectures
(2022-04-27)
Implementation of more refined structures at the nano to microscale is expected to advance applications in optics and photonics. This work presents the additive manufacturing of 3D luminescent microarchitectures emitting light in the visible range. A tailor-made organo-metallic resin suitable for two-photon lithography is developed, which upon thermal treatment in an oxygen-rich atmosphere allows the creation of silicon-free tetragonal (t-) and monoclinic (m-) ZrO₂. The approach is unique because the tailor-made ...
Aufsatz
Structural reorientation and compaction of porous MoS₂ coatings during wear testing
(2022-04-02)
Industrial upscaling frequently results in a different coating microstructure than the laboratory prototypes presented in the literature. Here, we investigate the wear behavior of physical vapor deposited (PVD) MoS2 coatings: A dense, nanocrystalline MoS2 coating, and a porous, prismatic-textured MoS2 coating. Transmission electron microscopy (TEM) investigations before and after wear testing evidence a crystallographic reorientation towards a basal texture in both samples. A basal texture is usually desirable due ...
Aufsatz
Microcantilever Fracture Tests of α-Cr Containing NiAl Bond Coats
(2022-01-08)
MCrAlY bond coats are widely used as oxidation-resistant coatings on superalloys. The major phase is the thermally stable intermetallic β-NiAl phase. The addition of Cr increases the oxidation and corrosion resistance but leads to the formation of α-Cr precipitates. Both phases are brittle and limit the fracture toughness of these coatings. To study the influence of thermal exposure and the resulting changing chemical composition on the fracture properties, the fracture toughness of both phases is measured by notched ...