TY - CONF A1 - Steinborn, Gabriele T1 - Stable aqeous niobium carbide suspensions for production of homogeneous hard materials N2 - Hard materials consist of a hard phase embedded in a metallic binder. In order to achieve high toughness and strength, it is necessary to have a perfect mixing of hard phase and binder, which is mainly achieved by ball milling. Niobium carbide (NbC) has a high potential to substitute tungsten carbide as hard material. The publication presents the development of stable homogeneous and de-agglomerated NbC-dispersions. To prevent agglomeration of the powder, stable suspensions were achieved by surface treatments with the dispersants (PD and HD), which resulted in a charge reversal from a negative to a positive zeta potential. This surface-modified powder guaranteed a stable re-dispersion in the binder suspension. Nickel powder was added as metallic binder. This suspension was suited for 3D-printing. The green samples could be sintered in vacuum or Argon atmosphere. T2 - 91. Jahrestagung der deutschen keramischen Gesellschaft CY - Freiberg, Germany DA - 07.03.2016 KW - Niobium carbide powder KW - Stable suspensions KW - Reduction of agglomerates PY - 2016 AN - OPUS4-35636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Dörfel, Ilona A1 - Steinborn, Gabriele A1 - Langner, Jeanette A1 - Krietsch, Arne A1 - Seeger, Stefan A1 - Österle, Werner A1 - Schmidt, Martin A1 - Bresch, Harald T1 - Dossier on titanium dioxide - Part 1/1 - NM 105 N2 - In November 2007, OECD’s Working Party on Manufactured Nanomaterials (WPMN) launched the Sponsorship Programme for the Testing of Manufactured Nanomaterials (hereafter the Testing Programme). The objective was to conduct specific tests, relevant to human health and environmental safety endpoints, on a variety of manufactured nanomaterials (MN). The outcomes of the Testing Programme were intended to assess the applicability of the existing test guidelines1 to nanomaterials, as well as to provide useful information on any intrinsic properties of MNs, which are different from the same bulk material with greater external dimensions. Understanding the properties of NMs is crucial to choose appropriate strategies for hazard identification, risk assessment or risk management measures. The Testing Programme involved delegations from OECD member countries, some non-member economies and other stakeholders. The broad international representation, from a range of delegations enabled the programme to pool expertise and resources without which this programme would not have been possible. KW - Nanomaterial KW - Nanoparticle KW - Sponsorship programme KW - Nano characterization PY - 2015 UR - http://www.oecd.org/env/ehs/nanosafety/dossier-on-silver-nanoparticles-part1-1.htm IS - 54 SP - 27 CY - Paris AN - OPUS4-35430 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Steinborn, Gabriele T1 - Wear behaviour of low IR-emission titanate ceramics under gross slip fretting conditions against steel and alpha-alumina N2 - The tribological behavior of different low infrared (IR) emission ceramic materials from the titanate group has been investigated at room temperature under gross slip fretting conditions against 100Cr6 ball bearing steel and α-alumina as the counterface materials. For all material pairs, friction and wear depended largely on the relative humidity of the environment. When paired with steel the low IR-emission ceramic disks showed higher wear resistance. Under dry conditions, almost no wear was found on the low IR-emission ceramic specimen. The high wear on the steel counter body is caused not only by tribo-oxidation, which is the main wear mechanism, but also by abrasion. In dry conditions a COF of 0.6 and in humid conditions a COF of 0.2 have been measured. When paired with α-alumina the results on wear are just opposite to those with steel counterbody and the low IR-emission ceramic materials show much lower wear resistance under all conditions. This is explained by the predominance of abrasion and the relatively large difference in hardness between the low IR-emission ceramic and α-alumina. In high humidity environments the results point to the formation of stable reaction layers causing lower friction and wear. KW - Gross slip fretting KW - Ceramic wear KW - Yttrium titanate KW - Zirconium titanate KW - Low IR-emission ceramics PY - 2014 DO - https://doi.org/10.1016/j.wear.2014.03.006 SN - 0043-1648 VL - 315 IS - 1-2 SP - 11 EP - 16 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-30504 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steinborn, Gabriele T1 - Improved wear resistant ceramics of metal incorporated NbC processed with gas pressure sintering N2 - Tungsten carbide (WC) dominates wear protection and machining since more than 90 years due to its hardness with an associated good toughness and high melting point. It was recently demonstrated that Niobium Carbides are wear resistant and show a better performing under cutting than WC grades. In order to profit of the good properties of Niobium Carbide, specific processing techniques need to be developed. The density of NbC is half of WC and offers colloidal processing for perfectly mixing NbC with metallic binder (up to 15 vol.-% Ni) and secondary carbide-particles. The used NbC-powder has an average particle size d50 of 3 micron measured by laser granulometry analysis. The true density was 7.68 g/cm3. An Oxygen content of the used NbC of 0.4 % is caused by residual slag content. It is possible to increase the stability of the NbC-suspensions and to reduce their viscosity by adding a specific dispersing agent. This surface-modified NbC powders (containing Ni)were uniaxially pressed and then gas pressure sintered in vacuum or Argon atmosphere. All samples reached more then 98 % of there theoretical density. The micrographs showed a homogenius distribution of the Ni-binder in the product. The tribological behaviour under dry sliding and oscillating up to 600 °C and the mechanical properties were studied. T2 - 92. Jahrestagung der Deutschen Keramischen Gesellschaft CY - Berlin, Germany DA - 19.03.2017 KW - NbC KW - Wear resistant KW - Gas pressure sintering PY - 2017 AN - OPUS4-40242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wäsche, Rolf A1 - Steinborn, Gabriele A1 - Woydt, Mathias T1 - Colloidal processing of metal bonded niobium carbide N2 - Manufacturing of Niobium carbide cermets with nickel binder and different additions of titanium carbide has been realized by colloidal processing in aqueous environment. T2 - 19. Plansee Seminar CY - Reutte, Austria DA - 29.05.2017 KW - NbC KW - TiC KW - Ni KW - Colloidal processing KW - Gas pressure sintering KW - Hardness PY - 2017 SP - HM 135/1 EP - HM 135/11 AN - OPUS4-40596 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Tzschichholz, Grit A1 - Steinborn, Gabriele A1 - Keller, M.H. A1 - Manara, J. T1 - Porous nano-composite materials with low emittance for reducing energy consumption T2 - Nanofair 2008 - New Ideas for Industry / 6th International Nanotechnology Symposium CY - Dresden, Germany DA - 2008-03-11 PY - 2008 SN - 978-3-18-092027-6 SN - 0083-5560 N1 - Serientitel: VDI-Berichte – Series title: VDI-Berichte IS - 2027 SP - 231 EP - 235 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-17746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tzschichholz, Grit A1 - Steinborn, Gabriele A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Klobes, Peter T1 - Characterisation of porous titania yttrium oxide compounds by mercury intrusion porosimetry and X-ray refractometry N2 - Aiming at ceramic materials of low thermal radiation emittance titania yttrium oxide ceramics have been prepared by sintering in air at 1,100 and 1,400 °C, respectively, and characterised. Due to its high infrared refractive index, average pore sizes up to 1 µm for optimal Mie scattering cross sections and over 35% porosity the material is a promising candidate for elevated temperature insulations. The essentially in large pore growth is achieved by graphitic nano and micro particle additives. The microstructure parameters of porosity, specific surface area, median and average pore sizes are determined by mercury intrusion porosimetry. Beyond this classical technique supplementary measurements by X-ray Absorption and X-ray refractometry reveal considerably larger average pore sizes due to closed pores not accessible for mercury. An additional advantage of the X-ray techniques is their non-destructive application, which allows other treatments afterwards. The combined application of both methods provides additional information and reliability in case of complex ceramic microstructures and may serve for improved developments of porous ceramics with optimised thermal scattering for energy savings in high temperature applications. KW - Porous ceramics KW - Mercury intrusion porosimetry KW - X-ray refractometry KW - Porosity KW - Specific surface area KW - Average pore size PY - 2011 DO - https://doi.org/10.1007/s10934-010-9358-4 SN - 1380-2224 SN - 1573-4854 VL - 18 IS - 1 SP - 83 EP - 88 PB - Kluwer CY - Dordrecht AN - OPUS4-22977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Paulick, Carl A1 - Steinborn, Gabriele A1 - Richter, V. A1 - Werner, M. T1 - Joining of ceramic components in the green state via LPIM N2 - It has been successfully demonstrated that ceramic materials can be joined in the green state without a second phase by using low pressure injection molded parts. The investigation of the joining interface revealed that a high quality interface can be achieved by carefully adjusting the different manufacturing steps. The use of monomodal particle size distribution in the used powder CT3000SG is inferior to a broader particle size distribution obtained by replacing 33% of the finer alumina powder by coarser CT1200SG. In this way the dewaxing process is significantly improved when the wall thickness of the part exceeds 3 mm. The investigation of the mechanical properties of the joined and sintered parts revealed, that the bending strength of the joined specimens achieved about 80 % of the unjoined, monolithic specimens. T2 - 4th International Conference on Advanced Materials and Processing CY - Hamilton, New Zealand DA - 2006-12-10 KW - Joining KW - Ceramics KW - Green state KW - Interface KW - Bending strength KW - Low pressure injection molding PY - 2005 UR - http://www.scientific.net/3-908453-89-5/207/ SN - 1022-6680 SN - 1662-8985 VL - 29-30 SP - 207 EP - 210 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-19001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Steinborn, Gabriele A1 - Scheler, S. A1 - Lehmann, J. T1 - Particle size determination at different concentrated Al2O3 and SiO2 nanopowder suspensions with the ultrasonic spectrometer DT 1200 T2 - WCPT6 2010 - World congress on particle technology CY - Nürnberg, Germany DA - 2010-04-26 KW - Partikelgrößenbestimmung KW - Zetapotential KW - Nanopulver PY - 2010 SN - 978-3-00-030570-2 IS - H H 1 0 00312 SP - 1 EP - 4 AN - OPUS4-22727 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steinborn, Gabriele T1 - Characterization of Ceramic nanoscale powders by PCS, AFM and TEM T2 - Partec CY - Nuremberg, Germany DA - 2004-03-16 PY - 2004 AN - OPUS4-5366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Klaffke, Dieter A1 - Steinborn, Gabriele T1 - Tribological testing of Ca-Ba infiltrated zirconia KW - Friction KW - Wear KW - Ca-Ba fluoride KW - Infiltration KW - Porous zirconia PY - 2005 UR - http://www.om.ugal.ro/AnnalsFasc8Tribology/pdf/2005/9-Annals2005-3-Wasche.pdf SN - 1221-4590 SN - 1220-0824 SP - 53 EP - 59 CY - Gala¸ti AN - OPUS4-12365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Bresch, Harald A1 - Dörfel, Ilona A1 - Steinborn, Gabriele A1 - Krietsch, Arne A1 - Langner, Jeanette A1 - Schmidt, Martin A1 - Österle, Werner A1 - Seeger, Stefan T1 - Physical-chemical characterization of NM105(P25) N2 - NM 105, Ti02 (P25) could not be ignited as dust layer and dispersed in air as dust/air-mixture as well. This dust is not dust explosible and the burning behaviour corresponds to Burning Class 1 (no Ignition). The results have shown that the tested sample is thus not combustible at all, because it is already oxidized completely. KW - OECD KW - WPMN KW - TiO2 KW - NM105 KW - P25 KW - Sponsorship programme PY - 2012 SP - 1 EP - 18 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-27322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wäsche, Rolf A1 - Steinborn, Gabriele A1 - Klaffke, Dieter ED - Somiya, S. T1 - Gas pressure sintering of SiCp-alumina composites made by gelcasting and their tribological properties N2 - COMPOSITE MATERIALS OF A 99.7 % ALPHA-ALUMINA MATRIX WITH PLATELETS OF SILICON CARBIDE (SICP) HAVE BEEN PREPARED BY GELCASTING. DENSIFICATION WAS CARRIED OUT BY GAS-PRESSURE SINTERING WITHOUT FURTHER SINTERING AIDS. FIVE DIFFERENT COMPOSITIONS WITH 0, 5, 10, 15, AND 20 VOL.% SICP RESP. HAVE BEEN INVESTIGATED AND TRIBOLOGICAL PROPERTIES WERE CHARACTERIZED. INCREASING AMOUNT OF SICP AS RIGID PARTICLES IN THE FINE GRAINED MATRIX COMPLICATE THE DENSIFICATION PROCESS. WITH THE APPLICATION OF 50 BAR AR PRESSURE DURING THE FINAL SINTERING STEP AT A TEMPERATURE OF 1700 DEGREE C THE DENSITY OF THE SAMPLES COULD BE INCREASED BY 3-5%. INVESTIGATION OF THE TRIBOLOGICAL PROPERTIES AGAINST STEEL AS A COUNTERBODY UNDER UNLUBRICATED OSCILLATING SLIDING CONDITIONS SHOWED A HIGH COEFFICIENT OF FRICTION AND AN INCREASING WEAR RATE UP TO A SICP CONTENT OF 10 VOL. % . AT 15 AND 20 VOL. % SICP RESP. BOTH THE COEFFICIENT OF FRICTION AND THE COEFFICIENT OF WEAR DROP DOWN. T2 - 3rd IUMRS International Conference on Advanced Materials (ICAM) CY - Tokyo, Japan DA - 1993-08-31 PY - 1994 SN - 0-444-81993-2 N1 - Serientitel: Transactions of the Materials Research Society of Japan – Series title: Transactions of the Materials Research Society of Japan IS - 16B SP - 791 EP - 794 PB - Elsevier CY - Amsterdam AN - OPUS4-1433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Steinborn, Gabriele T1 - Characterisation of the secondary properties of alumina - measuring the isoelectric point by a streaming potential method PY - 1997 SN - 0173-9913 SN - 0196-6219 VL - 74 IS - 5 SP - 235 EP - 239 PB - Göller CY - Baden-Baden AN - OPUS4-1434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Steinborn, Gabriele T1 - Influence of Slip Viscosity on the Mechanical Properties of High Purity Alumina made by Gelcasting KW - High purity alumina KW - Gelcasting KW - Solid content KW - Viscosity KW - Deairing KW - Bending strenght KW - Microstructure KW - Computertomography KW - Defect type PY - 1997 SN - 1013-9826 VL - 132 SP - 374 EP - 377 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-1435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Steinborn, Gabriele T1 - Influence of the Dispersants in Gelcasting of Nanosized TiN PY - 1997 SN - 0955-2219 SN - 1873-619X IS - 17 SP - 421 EP - 426 PB - Elsevier CY - Oxford AN - OPUS4-1429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steinborn, Gabriele A1 - Wäsche, Rolf A1 - Reichel, U. T1 - Fabrication of porous ceramics made from nano sized alumina powder by gelcasting N2 - The gelcasting process was used for manufacturing porous ceramic bodies from nano sized powders. 3 different powders with specific surface areas between 12 and 30 m²/g were used. Solid content of the corresponding slurries was dependent on the milling procedure and the use of a suitable dispersant. For bimodal GradeA powder solid content was as high as 58 vol%. For sintering temperatures between 1250 and 1600°C the porosity varied between 45 and 20%, whereas the pore radii varied between 50 and 91nm. The grain size of crystallites in the sintered microstructures was about 1um. The reflection ratio for visible light increased in comparison to a reference sample made from conventional powder from 0.8 to 0.95 in the wavelenght range around 400nm. T2 - 2nd International Conference on Shaping of Advanced Ceramics CY - Gent, Belgium DA - 2002-10-24 PY - 2002 SP - 103 EP - 108 AN - OPUS4-1813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - CONF A1 - Gemeinert, Marion A1 - Steinborn, Gabriele T1 - Stabilized dielectric barium titanate dispersions for sensor filling N2 - Resolution of special capacitive sensors can be improved enormously by replacement of the gaseous material between the capacitor plates by a ceramic dispersion with high permittivity. High dielectric liquid dispersions of ceramic submicron and nano barium titanate powders should be qualified as dielectric fluid with long-term shelf life for this use. Investigations for the production of stabilized barium titanate dispersions in aqueous and organic liquids by use of different dispersant aids were performed. Characterization of dispersed particles and agglomerates was done by use of zeta potential measurements for aqueous dispersions as well as particle sizing by laser diffraction, ultrasound spectroscopy and dynamic light scattering for aqueous and organic dispersions. Optimization of stability was evaluated by accelerated sedimentation measurements with an optical centrifuge. Best results were achieved for barium titanate dispersions in silicone oil. T2 - 91. Jahrestagung der deutschen keramischen Gesellschaft CY - Freiberg, Germany DA - 07.03.2016 KW - Stabilized dispersions KW - Barium titanate nanopowder KW - Particle size analysis PY - 2016 AN - OPUS4-35635 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Steinborn, Gabriele A1 - Tzschichholz, Grit A1 - Günster, Jens A1 - Keller, M.H. A1 - Manara, J. T1 - Porous TiO2-Y2O3 ceramics with specific infrared-optical properties N2 - The infrared-optical properties and particularly the emissivity of sintered ceramics depend on the material's bulk properties and structural properties such as porosity, pore size distribution and pore diameter. The infrared-optical properties can be varied across a wide range by specifically selecting the material's bulk and structural properties. A major concern of the present study is the development of a ceramic coating material with a total emissivity below 0.2 at a temperature of 800 °C. For this purpose, various samples of a TiO2-Y2O3 (TY) ceramic composite were produced with different properties. On variation in the Y2O3 content from 5 to 60 wt%, the porosity of the ceramic composites varies from 3 % to 47 % with the mean pore diameter lying in a range from 0.3 µm to 1.7 µm. The addition of graphitic pore builders increases the porosity up to 60 % and the mean pore diameter to a maximum of 15 µm. By optimizing the total porosity and the pore size of the TY ceramics, a total emissivity as low as 0.17 at 800 °C could be achieved. KW - Oxide ceramic KW - Porosity KW - Mean pore diameter KW - Infrared optical properties KW - Emissivity PY - 2011 DO - https://doi.org/10.4416/JCST2011-00011 SN - 2190-9385 VL - 2 IS - 3 SP - 183 EP - 190 PB - Göller CY - Baden-Baden AN - OPUS4-24551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Weba, Luciana A1 - Silbernagl, Dorothee A1 - Mota Gassó, Berta A1 - Höhne, Patrick A1 - Sturm, Heinz A1 - Pauli, Jutta A1 - Resch-Genger, Ute A1 - Steinborn, Gabriele ED - Khayat, Kamal Henry T1 - Influences of nano effects on the flow phenomena of self-compacting concrete N2 - Chemical admixtures like superplasticisers or stabilising agents are of ever increasing importance for modern concrete technology. They liberate the workability of concrete from its dependency on water content, and thus, open the gate towards innovative and future oriented concrete technologies such as selfcompacting concrete. Meanwhile admixtures have become common practice in concrete technology, but the understanding of these highly complex polymers in the entire concrete system lags far behind their application. Due to its complex time-dependent, multi-phase and multi-scale behaviour, flowable concrete systems are highly complicated and cannot be described comprehensively by simple models. It is therefore extremely challenging to identify the relevant parameters that predominantly control flow phenomena on different size scales, since these may occur on any scale between the nano scale (e.g. superplasticizer adsorption) and macro scale (e.g. grading of the aggregates). The present study discusses fundamental mechanisms at the interface between particle or hydrate surfaces and the fluid phase at a very early stage of concrete formation, and links these effects to macroscopic flow phenomena. Methods are discussed that appear promising interdisciplinary tools for enhancement of the understanding of the relevant interactions that are responsible for the macroscopic flow of flowable concrete. T2 - 8th International RILEM Symposium on Self-Compacting Concrete CY - Washington, D.C., USA DA - 15.05.2016 KW - Adsorption KW - Analytics KW - Hydration KW - Polycarboxylate ether KW - Rheology PY - 2016 SP - 245 EP - 254 AN - OPUS4-36882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -