Unlabelled: Rutile inclusions in almandine-spessartine garnet from a peraluminous pegmatoid from the Moldanubian zone (Bohemian Massif, AT) show distinct changes in aspect ratio, shape preferred orientations (SPO) and crystallographic orientation relationships (COR) along the transition between microstructurally different growth zones in the garnet core and rim. For identification of the COR characteristics we pool specific CORs based on their common axial relationship into three COR groups: Group 103/111, Group 001/111 and Group 001/100. The rutile inclusions in the garnet core domains are elongated along the four Grt 111 directions and are dominated by COR Group 103/111.
View Article and Find Full Text PDFThe interaction between ammonia (NH3) and (alumino)silicates is of fundamental and applied importance, yet the specifics of NH3 adsorption on silicate surfaces remain largely unexplored, mainly because of experimental challenges related to their electrically insulating nature. An example of this knowledge gap is evident in the context of ice nucleation on silicate dust, wherein the role of NH3 for ice nucleation remains debated. This study explores the fundamentals of the interaction between NH3 and microcline feldspar (KAlSi3O8), a common aluminosilicate with outstanding ice nucleation abilities.
View Article and Find Full Text PDFMicrocline feldspar (KAlSiO) is a common mineral with important roles in Earth's ecological balance. It participates in carbon, potassium, and water cycles, contributing to CO sequestration, soil formation, and atmospheric ice nucleation. To understand the fundamentals of these processes, it is essential to establish microcline's surface atomic structure and its interaction with the omnipresent water molecules.
View Article and Find Full Text PDFUnlabelled: A system of edge cracks was applied to polished (010) surfaces of K-rich gem-quality alkali feldspar by diffusion-mediated cation exchange between oriented feldspar plates and a Na-rich NaCl-KCl salt melt. The cation exchange produced a Na-rich layer at and beneath the specimen surface, and the associated strongly anisotropic lattice contraction lead to a tensile stress state at the specimen surface, which induced fracturing. Cation exchange along the newly formed crack flanks produced Na-enriched diffusion halos around the cracks, and the associated lattice contraction and tensile stress state caused continuous crack growth.
View Article and Find Full Text PDFWe used atom probe tomography to complement electron microscopy for the investigation of spinodal decomposition in alkali feldspar. To this end, gem-quality alkali feldspar of intermediate composition with a mole fraction of of the K end-member was prepared from Madagascar orthoclase by ion-exchange with (NaK)Cl molten salt. During subsequent annealing at and close to ambient pressure the ion-exchanged orthoclase unmixed producing a coherent lamellar intergrowth of Na-rich and K-rich lamellae.
View Article and Find Full Text PDFFocused ion beam (FIB) sample preparation technique in plan-view geometry allows direct correlations of the atomic structure study via transmission electron microscopy with micrometer-scale property measurements. However, one main technical difficulty is that a large amount of material must be removed underneath the specimen. Furthermore, directly monitoring the milling process is difficult unless very large material volumes surrounding the TEM specimen site are removed.
View Article and Find Full Text PDFBeilstein J Nanotechnol
May 2017
Molybdenum disulphide (MoS) thin films have received increasing interest as device-active layers in low-dimensional electronics and also as novel catalysts in electrochemical processes such as the hydrogen evolution reaction (HER) in electrochemical water splitting. For both types of applications, industrially scalable fabrication methods with good control over the MoS film properties are crucial. Here, we investigate scalable physical vapour deposition (PVD) of MoS films by magnetron sputtering.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
October 2016
Nanocomposite thin films comprised of metastable metal carbides in a carbon matrix have a wide variety of applications ranging from hard coatings to magnetics and energy storage and conversion. While their deposition using nonequilibrium techniques is established, the understanding of the dynamic evolution of such metastable nanocomposites under thermal equilibrium conditions at elevated temperatures during processing and during device operation remains limited. Here, we investigate sputter-deposited nanocomposites of metastable nickel carbide (NiC) nanocrystals in an amorphous carbon (a-C) matrix thermal postdeposition processing via complementary in situ X-ray diffractometry, in situ Raman spectroscopy, and in situ X-ray photoelectron spectroscopy.
View Article and Find Full Text PDFCation exchange experiments between gem quality sanidine [Formula: see text] and KCl melt produced chemical alteration of alkali feldspar starting at the grain surface and propagating inwards by highly anisotropic Na-K interdiffusion on the alkali sublattice. Diffusion fronts developing in -direction are very sharp, while diffusion fronts within the --plane are comparatively broad. Due to the composition dependence of the lattice parameters of alkali feldspar, the diffusion induced compositional heterogeneity induces coherency stress and elastic strain.
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