TY - JOUR A1 - Dörfel, Ilona A1 - Wäsche, Rolf A1 - Rabe, Torsten A1 - Steinborn, Gabriele T1 - Tribological Induced Microstructural Changes in Subsurface Layers of Si3N4-Based Materials KW - Tribologie PY - 1994 SN - 1013-9826 VL - 89-91 SP - 763 EP - 767 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dörfel, Ilona A1 - Urban, Ingrid T1 - TEM-Untersuchungen der Randzonenschädigung von Aluminiumoxidkeramiken nach Schleifbearbeitung N2 - Es werden elektronenmikroskopische Untersuchungsergebnisse an Al2O3-Keramiken, die verschiedenen Oberflächenbearbeitungsverfahren unterworfen wurden, vorgestellt. Die Untersuchungen dienen dem Ziel der Optimierung der Oberflächenbearbeitung von keramischen Werkstoffen, wobei der Einfluß leistungsfähiger Bearbeitungsverfahren auf die Ausbildung möglichst schädigungsarmer Oberflächenschichten, die keinen negativen Einfluß auf Festigkeitskennwerte aufweisen, betrachtet wird. Die Wirkung verschiedener Schleif- und Polierprozesse auf Oberflächenveränderungen bearbeiteter Werkstücke wird dargestellt. Es wurde sowohl die Mikrostruktur der geschädigten Randzonenschicht als auch die des unbeeinflußten Grundmaterials mit elektronenmikroskopischen Methoden charakterisiert. Die verschiedenen Schädigungsstadien gestatten eine Einschätzung der Stärke des Störungseintrages in das Material durch verschiedene Schleif- und Polierprozesse. KW - Elektronenmikroskop KW - Transmissionselektronenmikr. KW - Schleifen KW - Polieren KW - Aluminiumoxidkeramik KW - Randzonenschädigung KW - Oberflächenbearbeitung PY - 1996 U6 - https://doi.org/10.1002/mawe.19960270609 SN - 0933-5137 SN - 1521-4052 VL - 27 IS - 6 SP - 307 EP - 312 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-651 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Dörfel, Ilona A1 - Gesatzke, Wolfgang A1 - Rooch, Heidemarie A1 - Urban, Ingrid T1 - Charakterisierung tribologischer Kontakte mit FIB und TEM KW - FIB KW - TEM KW - Verbundwerkstoff KW - Bremse KW - Diamantschicht PY - 2004 SN - 0032-678X N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 41 IS - 4 SP - 166 EP - 179 PB - Hanser CY - München AN - OPUS4-3496 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ressel, P. A1 - Österle, Werner A1 - Urban, Ingrid A1 - Dörfel, Ilona A1 - Klein, A. A1 - Vogel, K. A1 - Kräutle, H. T1 - Transmission electron microscopy study of rapid thermally annealed Pd/Ge contacts on IN0.53Ga0.47As PY - 1996 SN - 0021-8979 SN - 1089-7550 VL - 88 SP - 3910 EP - 3914 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-2514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gajewski, Sven A1 - Maneck, Heinz-Eberhard A1 - Knoll, Uta A1 - Neubert, Dietmar A1 - Dörfel, Ilona A1 - Mach, Reinhard A1 - Strauß, Birgid A1 - Friedrich, Jörg Florian T1 - Purification of single walled carbon nanotubes by thermal gas phase oxidation N2 - Single walled carbon nanotubes (SWNT) have been produced in an electric arc discharge by using a graphite rod as anode which is filled with a powder mixture of graphite and metallic catalysts like nickel and yttrium. The soot material containing approximately a third of SWNT was collected from the cathode region as a soft, voluminous material. The main by-products in this process are amorphous carbon and graphitic nanoparticles which have to be removed by an appropriate purification process. The as-produced soot material was purified by gas phase oxidation in air at 355 °C. The oxidation of amorphous carbon in air is advantageous against wet chemical methods because it is better controllable. Thermogravimetric analysis and electron microscopy were used to investigate the oxidation behavior of the different kinds of carbon. Oxidation of SWNT and amorphous carbon occurs simultaneously even at moderate temperatures, whereas amorphous carbon is more rapidly oxidized than SWNT. For optimizing the purification procedure by gas phase oxidation, kinetic studies were used to determine the oxidation time for each component in the soot at a given temperature. So it is possible to remove the amorphous carbon quantitatively with minimal losses of SWNT. But it was found that graphitic nanoparticles have the highest stability against oxidation and could therefore not be quantitatively removed by this method without the complete destruction of SWNT. Therefore, the electric arc discharge process has to be a controlled process for minimum production of graphitic nanoparticles to obtain a material with a high content of SWNT. KW - Nanotubes KW - Cathodic arc discharge KW - Amorphous carbon KW - Oxidation PY - 2003 U6 - https://doi.org/10.1016/S0925-9635(02)00362-X SN - 0925-9635 VL - 12 IS - 3-7 SP - 816 EP - 820 PB - Elsevier CY - New York, NY AN - OPUS4-2516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Urban, Ingrid A1 - Dörfel, Ilona A1 - Österle, Werner A1 - Schierhorn, Eike T1 - Interfaces between hard coating systems and substrates T2 - 11th European Conference on Electron Microscopy (EUREM-11) CY - Dublin, Ireland DA - 1996-08-26 PY - 1996 SN - 2-9600163-0-0 PB - CESM, Committee of European Societies of Microscopy CY - Brussels AN - OPUS4-2545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Skopp, André A1 - Dörfel, Ilona A1 - Witke, Klaus T1 - Wear Engineering Oxides / Antiwear Oxides KW - Oxid KW - Hochtemperatur KW - Keramik KW - Reibung PY - 1999 SN - 1040-2004 SN - 1547-397X IS - 42,1 SP - 21 EP - 31 PB - Taylor & Francis CY - Philadelphia, Pa. AN - OPUS4-711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rudolf, A. A1 - Kaiser, W.-D. A1 - Dörfel, Ilona A1 - Engelhardt, Monika A1 - Österle, Werner T1 - Zum Zusammenhang von Filiformkorrosion und Gefüge von Aluminiumlegierungen, Teil I PY - 2002 SN - 0002-6689 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 78 IS - 7/8 SP - 596 EP - 601 PB - Giesel CY - Isernhagen AN - OPUS4-2074 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rudolf, A. A1 - Kaiser, W.-D. A1 - Dörfel, Ilona A1 - Engelhardt, Monika A1 - Österle, Werner T1 - Zum Zusammenhang von Filiformkorrosion und Gefüge von Aluminiumlegierungen, Teil II PY - 2002 SN - 0002-6689 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 78 IS - 11 SP - 994 EP - 1000 PB - Giesel CY - Isernhagen AN - OPUS4-2075 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Dörfel, Ilona A1 - Effner, Ute A1 - Glaubitz, Steffen A1 - Österle, Werner A1 - Rudolph, Edith ED - Ziegler, G. T1 - Charakterisierung hochfester ZrO2-Werkstoffe T2 - Werkstoffwoche '96 (WW) CY - Stuttgart, Deutschland DA - 1996-05-28 PY - 1997 SN - 3-88355-234-8 VL - 6 SP - 691 EP - 702 PB - DGM Informationsges. CY - Frankfurt AN - OPUS4-2635 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Dörfel, Ilona A1 - Urban, Ingrid A1 - Reier, T. A1 - Schultze, J. T1 - XPS and XTEM study of AlN formation by N+2 implantation of aluminium N2 - X-ray photoelectron spectroscopy (XPS) and cross-sectional transmission electron microscopy (XTEM) were used to study the formation of AlN films by N+2 ion implantation of aluminium at energies of 3 keV and 100 keV. In both cases, a two-stage mechanism was found, comprising first the oriented precipitation of small particles of the hexagonal AlN-phase, followed by growth and coalescence finally forming a continuous AlN-layer while increasing the implantation dose from 1×1017 cm-2 to 2×1017 cm-2. The results of both methods are in excellent agreement and furthermore provide complementary information concerning chemical composition and binding energies as well as microstructural details. KW - AIN KW - Aluminium KW - N2+ KW - Implantation KW - XPS KW - XTEM PY - 1998 U6 - https://doi.org/10.1016/S0257-8972(98)00355-7 SN - 0257-8972 VL - 102 IS - 1-2 SP - 168 EP - 174 PB - Elsevier Science CY - Lausanne AN - OPUS4-2363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dörfel, Ilona A1 - Österle, Werner A1 - Urban, Ingrid A1 - Bouzy, E. T1 - Microstructural characterization of binary and ternary hard coating systems for wear protection - Part I: PVD coatings N2 - Different wear-resistant coatings produced by physical vapour deposition (PVD) were characterized with the aid of cross-sectional transmission electron microscopy (XTEM). All coating systems were optimized by the producers and exhibited good properties with respect to their special applications. The microstructure, texture and chemical composition of binary and ternary systems produced by the arc process [TiN, CrN, Cr2N (Ti, Cr)N on steel substrates] and magnetron sputtering process [TiN, CrN on steel substrates, (Ti, Al)N on Si-substrate] were investigated. All coatings had a more or less columnar microstructure, which was interrupted by interlayers in some cases. Whereas arc coatings always did show some kind of substrate modification, the latter was not observed after magnetron sputtering. Electron diffraction normally revealed a mono-phase fcc structure, except at sites very near to the interface. Only for the systems Cr–N and (Ti, Cr)–N were different additional phases observed at low nitrogen partial pressures. KW - Arc bond sputtering KW - Arc deposition KW - Magnetron sputtering KW - TEM KW - XTEM PY - 1999 UR - http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVV-3VTRSCY-G&_user=963821&_coverDate=01%2F29%2F1999&_rdoc=14&_fmt=summary&_orig=browse&_srch=doc-info(%23toc%235544%231999%23998889997%2360972%23FLA%23display%23Volume)&_cdi=5544&_sort=d&_docanch U6 - https://doi.org/10.1016/S0257-8972(98)00735-X SN - 0257-8972 VL - 111 IS - 2-3 SP - 199 EP - 209 PB - Elsevier Science CY - Lausanne AN - OPUS4-2364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dörfel, Ilona A1 - Österle, Werner A1 - Urban, Ingrid A1 - Bouzy, E. A1 - Morlok, O. T1 - Microstructural characterization of binary and ternary hard coating sytems for wear protection - Part II: Ti(CN) PACVD coatings KW - Microstructure KW - PACVD KW - Solid lubrication KW - Texture KW - TiC KW - TiN KW - Ti(CN) PY - 1999 SN - 0257-8972 VL - 116-119 SP - 898 EP - 905 PB - Elsevier Science CY - Lausanne AN - OPUS4-2365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dörfel, Ilona A1 - Gesatzke, Wolfgang A1 - Österle, Werner A1 - Skopp, André T1 - Characterization of defects in dry-pressed green bodies PY - 1994 SN - 1013-9826 VL - 89-91 SP - 763 EP - 767 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-2413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nofz, Marianne A1 - Stösser, R. A1 - Scholz, G. A1 - Dörfel, Ilona A1 - Schultze, Dietrich T1 - The thermally induced transformation of pseudoboehmite gels - a comparison of the effects of corundum seeding and iron doping N2 - The transformation of doped or seeded pseudoboehmite to corundum was studied by combining thermal analysis, X-ray diffraction, transmission electron microscopy, and electron paramagnetic resonance spectroscopy. The temperature of phase transformation to corundum was lowered by about 130 °C when Fe3+ or corundum seeds were added to the sols. Action of Fe3+ ions depends on the actual degree of thermally induced transformation of pseudoboehmite via transition aluminas to corundum and the ability of these alumina phases to incorporate Fe3+ ions. These ions tend to aggregate with increasing iron concentration of the alumina phases and can work as nucleation centers. Small (not, vert, similar20 nm) corundum particles act as active nucleation sites whereas larger grains (200–400 nm) also present in the samples are less effective. For the first time trapping and stabilization of NO2 molecules in transition aluminas formed by a sol–gel route was shown. KW - Grain size KW - Sol-gel processes KW - Electron microscopy KW - X-ray methods KW - Al2O3 PY - 2005 U6 - https://doi.org/10.1016/j.jeurceramsoc.2004.04.014 SN - 0955-2219 SN - 1873-619X VL - 25 IS - 7 SP - 1095 EP - 1107 PB - Elsevier CY - Oxford AN - OPUS4-7455 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wäsche, Rolf A1 - Klaffke, Dieter A1 - Woydt, Mathias A1 - Dörfel, Ilona T1 - Interface formation by tribo-oxidation in SiC based ceramics T2 - AIST-BAM Symposium on Materials Surface Technology in Twin Institute Programme CY - Tsukuba, Japan DA - 2003-02-18 PY - 2003 SP - 1 EP - 4 AN - OPUS4-12051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Klaffke, Dieter A1 - Woydt, Mathias A1 - Dörfel, Ilona T1 - Structure of the interface in SiC-based ceramic composites formed by tribo-oxidation under dry sliding conditions PY - 2004 SN - 1042-1122 VL - 146 SP - 401 EP - 407 PB - American Ceramic Society CY - Westerville, Ohio AN - OPUS4-12053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yarim, Rasim A1 - Wäsche, Rolf A1 - Woydt, Mathias A1 - Dörfel, Ilona T1 - Analysis of wear protecting oxide layers in the system SiC-TiC-TiB2 formed in-situ at high temperatures T2 - AIST-BAM Symposium on Materials Surface Technology in Twin Institute Programme CY - Tsukuba, Japan DA - 2003-02-18 PY - 2003 SP - 5 EP - 8 AN - OPUS4-12057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dörfel, Ilona A1 - Rooch, Heidemarie A1 - Österle, Werner T1 - Microstructural differences between two Zr(C,N) coatings revealed by analytical transmission electron microscopy N2 - The microstructures of two samples of a Zr(C,N) coating on steel, which unexpectedly differed in their tribological properties, were investigated by analytical transmission electron microscopy. The samples were produced by a cathodic arc evaporation process in two commercial coating devices under similar coating conditions with the exception of the number of Zr targets. The source of the differing tribological properties of the samples was detected by analytical transmission electron microscopy (TEM) methods energy-dispersive X-ray spectroscopy (EDX), energy filtering TEM (EFTEM), electron diffraction, high resolution electron microscopy, and high angel annular dark field. The TEM preparation and the results of the TEM investigations are shown in detail. The origin of the unexpected behavior was determined to be a nano-scale multilayer structure that existed only in the tribologically superior specimen. EDX and EFTEM investigations indicated enrichment in oxygen at the interface between coating and steel substrate in the tribologically inferior sample. Findings of the microstructural configuration were obtained by taking a closer look at the structure and comparing the results of the several analytical TEM techniques. This allows the allocation of the concentration fluctuations in N, C, and Zr to the two thickness fractions of the nano multilayers and a local correlation of the identified minority phase Zr3(C,N)4 to the higher N content in the narrower type of the multilayer fraction of the sample with the excellent tribological properties. The minority phase Zr3(C,N)4 is randomly distributed in the sample with the defective tribological properties. Coating conditions are not topic of this work, but after discussion of the TEM results, the fact that one of the coating devices worked with one Zr target and the other one with two, could be identified as cause for the formation of the nano multilayer structure in the sample with the superior tribological properties. KW - Analytical transmission electron microscopy KW - Tribological coatings KW - Multilayers KW - Analytical TEM KW - Coatings KW - Nano-multilayer PY - 2012 U6 - https://doi.org/10.1016/j.tsf.2012.02.051 SN - 0040-6090 VL - 520 IS - 13 SP - 4275 EP - 4281 PB - Elsevier CY - Amsterdam AN - OPUS4-25657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer-Plath, Asmus A1 - Orts Gil, Guillermo A1 - Petrov, Sergej A1 - Oleszak, Franz A1 - Maneck, Heinz-Eberhard A1 - Dörfel, Ilona A1 - Haase, Oskar A1 - Richter, Silke A1 - Mach, Reinhard T1 - Plasma-thermal purification and annealing of carbon nanotubes N2 - We have developed a very fast and entirely gas-phase based purification technique for carbon nanotubes (CNT) that allows removing metal and metal oxide impurities with high effectiveness. CNT agglomerates from chemical vapor deposition (CVD) synthesis which contained carbon encapsulated catalysts were injected into an atmospheric plasma torch. Very high heating rates allow for quasi-instantaneous vaporization of catalyst particles. This way, metal vapors are hyposized to break mechanically instable encapsulations and effuse from incomplete ones faster than thermally induced graphitization stabilizes such particle encapsulations. The ash content of multi-walled (MW) CNT samples was reduced to less than 15% of the initial value within a few milliseconds. Also the metal content of single-walled (SW) CNT agglomerates was significantly reduced. Repeated injection of CNT agglomerates into the plasma torch resulted in higher-purity products of improved structural integrity and increased oxidation resistance. PY - 2012 U6 - https://doi.org/10.1016/j.carbon.2012.04.049 SN - 0008-6223 SN - 1873-3891 VL - 50 IS - 10 SP - 3934 EP - 3942 PB - Pergamon Press CY - New York, NY AN - OPUS4-25986 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -