TY - THES A1 - Schulz, Wencke T1 - Abscheidung und Charakterisierung von Sol-Gel-Aluminiumoxidschichten auf kommerziellen Kraftwerksstählen zum Schutz gegen Korrosion bei Oxyfuel-Verbrennung N2 - The objective of the present work was the investigation and demonstration of the potential of sol-gel alumina layers as corrosion protection of commercial power plant steels under oxyfuel conditions. The starting points of this work were modified Yoldas-sols which were developed in the BAM-department 5.6. These sols were suitable for the spin-coating method only. The application of coatings on tubes by spin-coating is impossible. Therefore, the chemical composition of the modified Yoldas-sol had to be adapted to the dip- and spray-coating techniques. Exclusively the sol with the composition s-0.52-6-1.5 with a nitrate/aluminium ratio of 0.52; a solid content of 6 wt.% and a PVP (binder) content of 1.5 wt.% could fulfill the necessary criteria: long-term stability; formation of a dense, crack-free and well adhered layer on polished metal surfaces; as well as high protective abilities against corrosion in H2O-CO2-O2-SO2. The commercial power plant steel X20CrMoV12-1 (X20) and the steel X12Cr13 were successfully coated with the sol s-0.52-6-1.5 by means of the dip-coating method. An at least 400 nm thick alumina layer (δ-Al2O3) is necessary to ensure the corrosion protection of these steels. The corrosion of the coated samples compared to that of the uncoated ones was significantly reduced, even after 1000 h of exposure in a H2O-CO2-O2-SO2 atmosphere at 600°C. Sulfur and carbon were not detected at the substrate surface or beneath the coating. Hence the transport of the flue gas components SO2 and CO2 into as well as through the alumina layer could be hindered. The diffusion of the alloying elements (Cr, Mn, Si) into the alumina layer resulted in the formation of mixed oxides like δ-(Al,Cr)2O3. Formation of such phases considerably contributed to the corrosion protection. The long-term stability of the sol s-0.52-6-1.5 and the high protective abilities of the alumina layer on commercial power plant steels provide a good basis for an industrial application. KW - TEM KW - Alumina KW - Coating KW - Oxyfuel KW - Steel KW - High-Temperature Corrosion PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:188-fudissthesis000000102280-0 DO - https://doi.org/10.17169/refubium-6842 SP - 0 EP - 179 PB - Freie Universität CY - Berlin AN - OPUS4-50310 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - Focused ion beam techniques beyond the ordinary - Methodological developments within ADVENT N2 - This poster presents the focused ion beam preparation methodologies developed within the framework of the EU funded EURAMET project ADVENT (Advanced Energy-Saving Technology). It summarises the key breakthroughs achieved for various in situ investigation techniques, e.g. in situ experiments at the Synchrotron facility BESSY II (IR-SNOM and XRS), TEM and SMM instrumentation. The created experimental devices from diverse thin-film semiconductor materials paved the way to dynamic structural studies bearing the potential to determine nanoscale correlations between strain and electric fields and, moreover, for the fundamental development of new in situ capabilities. N2 - Dieses Poster zeigt die FIB Präparationstechniquen, die im Rahmen des EU-finanzierten EURAMET-Projekts ADVENT (Advanced Energy Saving Technology) entwickelt wurden. Es fasst die wichtigsten Errungenschaften zusammen, die für verschiedene in situ Untersuchungstechniken erzielt wurden, z.B. situ-Experimente in dem Synchrotronring BESSY II (IR-SNOM und XRS), in situ TEM Experimente und für die SMM Technik. Die experimentellen Probenstrukturen, die aus verschiedenen Dünnschicht-Halbleitermaterialien erzeugt wurden, ebneten den Weg für dynamische Strukturstudien, die das Potenzial haben, nanoskalige Korrelationen zwischen Dehnung und elektrischen Feldern zu bestimmen und darüber hinaus neue in situ Messmethoden zu entwickeln. T2 - Final Meeting CY - Online Meeting DA - 30.06.2020 KW - FIB KW - Sample preparation KW - In situ KW - TEM KW - AFM PY - 2020 AN - OPUS4-51606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bettge, Dirk A1 - Österle, Werner T1 - “Cube slip” in near-[111] oriented specimens of a single-crystal nickel-base superalloy N2 - In the past few years, it has been discussed with increasing frequency, whether cube slip does occur in gamma' hardened nickel-base superalloys. Occurrence of cube slip has consequences for the modeling of orientation dependence of the CRSS. Until now, there are only few experimental investigations. In principle, cube slip should be possible in primitive cubic lattices (e.g. L12 ordered gamma' phase) but not in face centered cubic ones (e.g. Ni solid solution). The most favourable specimen orientations are near [111], where the Schmid factors for this type of glide exceed those for octahedral systems. There are two basic methods to detect cube slip: macroscopic slip trace analysis and Transmission electron microscopy (TEM) investigation of the dislocation structure. Few observations of cube slip by macroscopic slip traces are reported in the literature. But it is still uncertain under which test conditions cube slip occurs and what the dislocation mechanisms are. Cube slip was observed during tensile or compression tests of several first generation superalloys, but it seems not to occur during shear creep deformation (e.g. CMSX-4 at 980°C), and it is also lacking under conventional tensile or compression loading, if the gmma' particles are small. No observations were ever reported of dislocations gliding on {001} planes in matrix channels. KW - Cube slip KW - Nickel-base superalloy KW - Dislocations KW - TEM PY - 1999 DO - https://doi.org/10.1016/S1359-6462(98)00446-1 SN - 1359-6462 VL - 40 IS - 4 SP - 389 EP - 395 PB - Elsevier AN - OPUS4-38220 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. I. A1 - Petrushin, N. V. A1 - Link, T. A1 - Nolze, Gert A1 - Loshchinin, Yu. V. A1 - Gerstein, G. T1 - Thermal stability of the structure of a heat-resistant cobalt alloy hardened with intermetallic γ'-phase precipitates N2 - The thermal stability of the microstructure of a heat-resistant cobalt alloy, which consists of a γ solid solution strengthened with γ'-phase precipitates, has been studied. The temperature behavior of the dissolution of the hardening γ' phase and the kinetics of its coarsening at 700 and 800°C have been determined. It is found that, during prolonged annealing at 800°C, the γ' → β phase transformation occurs. KW - Superalloy KW - Microstructure KW - Hardening KW - Electron backscatter diffraction KW - TEM PY - 2016 DO - https://doi.org/10.1134/S0036029516040078 SN - 0036-0295 VL - 2016 IS - 4 SP - 286 EP - 291 PB - Pleiades Publishing AN - OPUS4-37768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radunz, Sebastian T1 - Investigation of upconverting nanoparticle growth utilizing in-situ luminescence monitoring in combination with offline small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) N2 - - UCNPs were succesfully synthesized and characterized - Various stages of UCNP growth were tracked using different analytical methods including real time in-situ & time-resolved luminescence spectroscopy, SAXS and TEM measurements - Additional size determination will be performed using inductively coupled plasma - mass spectrometry (ICP-MS) T2 - BAM-PTB-Nanoworkshop CY - PTB, Berlin, Germany DA - 14.05.2018 KW - Rare earth nanoparticles KW - Upconversion KW - TEM KW - SAXS PY - 2018 AN - OPUS4-45884 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo T1 - Mechanisms of M23C6 Carbide Precipitation in Ni-Base Superalloy Single Crystals N2 - The demand for improved castability and low angle grain boundary (LAGB) resistance has led to the addition of low contents of e.g., B, Hf, Zr or C, into large industrial gas turbine components made of Ni-base superalloy single crystals (SXs). Due to the long-term application of Ni-base superalloy SX components in the temperature regime > 1000 °C, the formation of carbides is highly probable, which could jeopardize mechanical properties, such as high cycle fatigue. In the present contribution, the effect of internal and external stresses on the nucleation and growth characteristics of M23C6 carbides is investigated. Creep experiments are performed on the Ni-base superalloy SX LEK 94, which shows a low C concentration (= 0.1 at. %), at 1020 °C under parallel and circularly notched tensile specimens at a nominal stress of 160 MPa in the crystallographic direction [001]. The carbides are then characterized via scanning (S) and transmission (T) electron microscopy (EM). Nucleation is enhanced in the dendritic cores, often as coalesced colonies, extending over micrometers within M-rich (M: Cr, Re, W, Mo) γ channels. Lath shapes with facets on {100} (parallel to growth direction) and {111} are common. These facets exist since early stages (Fig.1a) and later develop misfit dislocations (Fig.1b), preserving the orientation relationship {100}γ || {100}M23C6. Fig. 1c shows a region from the creep gage, where carbides interact with superdislocations in the γ’ phase. Possible mechanisms are discussed. T2 - European Congress and Exhibition on Advanced Materials and Processes (EUROMAT) 2017 CY - Thessaloniki, Greece DA - 17.09.2017 KW - Superalloy KW - TEM KW - Carbide KW - Nucleation KW - Pore KW - Dislocation PY - 2017 AN - OPUS4-42176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Report VAMAS/TWA 37 "Quantitative Microstructural Analysis" & Liaison with ISO/TC 202 "Microbeam Analysis" N2 - The progress in activities on Quantitative MicroStructural Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 Microbeam Analysis is presented and discussed with respect to the identification and launching corresponding VAMAS projects. The ongoing projects "Development of guidelines for reproducible TEM specimen preparation by FIB processing", "Measurement of dislocation density in metallic materials by Transmission Electron Microscope (TEM)", "Repeatability of high angular resolution electron backscatter diffraction (HR-EBSD) analysis for elastic strain measurements", and "Measurement of grain size and distribution of nanocrystalline nickel by using Transmission Kikuchi Diffraction (TKD) in SEM" are presented in detail. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 49th Steering Committee Meeting CY - Rio de Janeiro, Brazil DA - 23.09.2024 KW - VAMAS KW - Interlaboratory comparison KW - Microbeam Analysis KW - FIB KW - SEM KW - TEM KW - Sample preparation PY - 2024 UR - www.vamas.org/twa37/index.html AN - OPUS4-61388 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rockenhäuser, Christian T1 - S-phase growth and coarsening of alloy 2618A during ageing and creep N2 - The S-phase growth and coarsening of alloy 2618A during Ageing and Creep is discussed and presented for an expert audience. T2 - Microscopy Conference 2017 (MC2017) CY - Lausanne, Switzerland DA - 20.08.2017 KW - Aluminium alloy 2618A KW - TEM KW - Coarsening KW - S-phase PY - 2017 AN - OPUS4-41700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werner, Tiago T1 - Ermüdung von additiv gefertigtem Stahl AISI 316L: Zyklische plastische Verformung N2 - Das zyklische plastische Verformungsverhalten von additiv gefertigtem Edelstahl AISI 316L wurde in dehnungsgeregelten Kurzzeitfestigkeitsversuchen (LCF-Versuchen) untersucht. Dabei wurden zwei Wärmebehandlungszustände betrachtet: Beim ersten Zustand war die fertigungsbedingte zelluläre Struktur vorhanden, während sie durch die zweite Wärmebehandlung aufgelöst wurde. Untersuchungen im Transmissions-Elektronen-Mikroskop (TEM) zeigten, dass die zyklische Verformung die Zellstruktur lokal zerstörte und Gleitbänder entstanden, was die Entfestigung in diesem Fall erklärt. Für Material ohne Zellstrukturen resultierten nach zyklischer Verformung ähnliche Versetzungsstrukturen wie in konventionell gefertigtem (warmgewalzten) Material. T2 - OVGU-Kolloquium (BMDK des IWF) CY - Magdeburg, Germany DA - 23.06.2022 KW - Additive Fertigung KW - Kurzzeitfestigkeit KW - Mikrostrukturentwicklung KW - Versetzungsstrukturen KW - TEM PY - 2022 AN - OPUS4-56789 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dörfel, Ilona T1 - Microstructure of alumina coating on steel P92 after thermal cycling N2 - 1. Introduction Alumina coatings are one possibility to increase the corrosion resistance, lifetime and application range of thermally loaded steel components, e.g. in modern power plants where the use of the Oxy-fuel technology corrosive fuel gas (H2O-CO2-O2-SO2 at 650 °C) affects the steel parts. In previous investigations the efficacy of protective alumina coatings on steel P 92 under those conditions was demonstrated. A shutdown and re-start of power plants or parts of them causes thermal stresses of the components which can cause detrimental effects like microstructural changes in the steel itself, changes in its oxidation behavior, delamination or microstructural changes in the coating. All those effects can lead to failure of the components, resulting in lifetime reduction. 2. Objectives As a first step, we concentrate on the influence of thermal cycling tests and observe the impact on the microstructure of the coating and the interface in laboratory air. These investigations will help understanding the processes which occur, show directions of potentially necessary changes of the coating due to improved thermal stress behaviour. 3. Materials & methods P 92 is a ferritic-martensitic steel, containing 9% Cr which forms protective Cr-oxide-rich scales in dry environments and non-protective ones in water-containing environments. Coupons of P 92, having ground surfaces, were dip-coated via a sol-gel process and subjected to thermal cycling for 500 h (1000 cycles) in laboratory air in a temperature range between room temperature and 660° C. The resulting mass loss was determined by weighing. Samples for TEM investigations were produced as cross sections normal to the sample surface by FIB preparation (Quanta 3D, (FEI)). The TEM/STEM investigations were performed using a JEM2200FS (JEOL) operated at 200 kV. The microstructure of the coating and the interface after cycling tests was characterized via TEM, HREM, and STEM images, electron diffraction as well as EDX and EFTEM methods. 4. Results At steep edges in the surface profile the coating was imperfect and cracks have formed during the thermal cycling. Flat surface regions are well-covered. The whole interface region between the steel and the coating shows a dense Cr-oxide-rich zone, which can form protective regions in case of local failure. The Cr-oxide zone is followed by a region of mixed oxides, containing Cr, Mn, Fe, and Al in variable composition, to which a porous δ-Al2O3 zone is joined. 5. Conclusions • Alumina coatings promote the formation of dense, Cr-rich zones at the interface, which makes the system self-healing. • These zones are stable during thermal stresses, even in regions with cracked coatings. • They cause reduction of outward diffusion and mass loss during thermal cycling. T2 - MC2017 CY - Lausanne, Switzerland DA - 21.08.2017 KW - Coating KW - Thermal cycling KW - TEM PY - 2017 UR - https://www.mc2017.ch/general-information/downloads/ AN - OPUS4-41724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -