TY - CONF A1 - Bäßler, Ralph A1 - Le, Quynh Hoa A1 - Yevtushenko, Oleksandra A1 - Bettge, Dirk T1 - Corrosion Aspects for Materials to be Used in CC(U)S Applications N2 - This contribution provides current findings regarding materials susceptibility for carbon capture, utilization and storage (CCUS) applications. Basing on results gathered in 2 German long-term projects (COORAL and CLUSTER) suitable materials are introduced as well as dominating impurities of the CO2-stream and corrosion mechanisms. Investigations cover the whole CCUS process chain and provide material recommendations for certain parts. T2 - 1st International Conference on Corrosion Protection and Application CY - Chongqing, China DA - 09.09.2019 KW - Carbon KW - Capture KW - Storage KW - Utilization KW - CCS KW - CCU KW - CO2 KW - Corrosion PY - 2019 AN - OPUS4-49302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Buljak, V. A1 - Bruno, Giovanni T1 - Modeling of elastic modulus evolution in porous ceramics due to thermally induced cracking N2 - Within polycrystalline porous ceramics used in automotive applications as diesel particulate filters, it is evidenced that during cooling from firing temperature micro cracks are gradually formed. The cracks are formed as a consequence of strong thermal anisotropy of grains. Typically these micro cracks are granting better thermal shock resistance, with respect to dense materials, but reduce stiffness. The reduction can be quantified by measuring the drop in elastic properties of bulk material which, depending on the level of porosity, can decrease even by 50% with respect to its value at high temperature. It is further observed that upon subsequent heating these cracks are closing and partially or totally healing at very high temperatures. Such peculiar behavior results in partial or complete recovery of the elastic properties of bulk material upon completing one thermal cycle. Despite its evident practical application, still there is no constitutive description of this phenomenon, capable of predicting the evolution of Young's modulus as a function of temperature history. For reliable numerical simulation of this phenomenon, it is required to model fracture. To model inter-crystalline fracture, an effective strategy is to use cohesive elements, since crack patterns are a priori known. Major limitation of this approach is that the cohesive elements already implemented within commercial codes cannot take into account crack healing upon subsequent heating. In this study new cohesive element is developed and numerically implemented within ABAQUS commercial finite element code, capable to model crack opening, closing and healing. Further on, a computer code is generated to build numerical model of porous ceramic specimens that takes into account experimentally measured crystallographic orientation and porosity, and models the microstructure by using Voronoi polygons. The developed numerical tools serve as a framework for more realistic simulations, required to study the hysteresis in elastic properties within porous ceramics provoked by thermal cyclic. In a subsequent phase, an inverse analysis procedure is developed, in which macroscopic properties are used to calibrate parameters entering into micro crack model. The approach is centered on a minimization of a discrepancy function designed to quantify the difference between experimentally measured quantities and their computed counterpart. The model is calibrated on the basis of experimental data regarding the drop of bulk Young's modulus with decrease of temperature. Developed procedure is tested with porous cordierite sample, and obtained results are quit promising despite the current limitation of using only two-dimensional model. T2 - European Ceramic Society Conference 2019 CY - Turin, Italy DA - 16.06.2019 KW - Microcracking KW - Cordierite KW - Inverse Problems KW - Finite elements KW - Cohesive Elements KW - Young's modulus PY - 2019 AN - OPUS4-48926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Thiede, Tobias A1 - Mishurova, Tatiana A1 - Ulbricht, Alexander A1 - Sprengel, Maximilian A1 - Kromm, Arne A1 - Serrano Munoz, Itziar A1 - Evans, Alexander T1 - Diffraction-based experimental determination of Residual Stress in AM parts: A critical discussion N2 - Additive manufacturing (AM) technologies have experienced an exceedingly rapid growth, not always paralleled by the knowledge about the materials properties and performance. In particular, residual stress (RS) has been soon recognized as an issue in AM parts, so that parts are always post-heat-treated. Moreover, much effort has been spent on simulating RS, especially using finite element methods. The experimental determination of RS has thereby become increasingly important, and even simple data constitute (to date) a piece of knowledge to fill the above-mentioned gap. In particular, diffraction methods, which are basically non-destructive, offer enormous possibilities to gain knowledge on real components, since neutrons and synchrotron radiation can penetrate even heavy metals up to several millimeters (or even centimeters). Indeed, some success has been obtained, and the knowledge about the origins of the RS fields, as well as their variation as a consequence of heat or mechanical treatments, has been greatly expanded. In this talk, a few success stories will be outlined. It will be shown how the determination of RS in metallic parts (with focus on those produced by laser powder bed fusion) has even allowed showing that process parameters that were considered unimportant play a major role in the onset of stress. However, while RS is starting to be considered in the part design, deposition strategy (e.g. build plate temperature), and even in the definition of the relevant metric to assess the quality of a part, much is still to be investigated about the hypotheses underlying its experimental determination. Therefore, some aspects to be aware of, or even to date unclear will also be discussed, such as the determination of the reference unstrained samples and of the principal axes of stress. All these aspects will draw the path towards a comprehensive understanding of the process-structure-performance relationships in AM materials and parts. T2 - MSTAM 2019 CY - Bremen, Germany DA - 10.12.2019 KW - Elastic Constants KW - Residual Stress KW - Additive Manufacturing KW - Neutron Diffraction PY - 2019 AN - OPUS4-50020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Engineering applications of neutrons at the ILL: retrospective, present, and future N2 - In this talk, the evolution of the demand for engineering applications of neutrons at the ILL in the last 10 years is presented. It is shown that small angle neutron scattering and diffraction are highly demanded by the materials science community. Further development in the field is foreseen, with the use of in-situ (furnace, tension/compression rig, humidity cells, etc.) techniques to associate to the neutron techniques. T2 - ILL 100th Scientific Council CY - Grenoble, France DA - 09.04.2019 KW - Neutron Diffraction KW - Residual Stress KW - Small Angle Neutron Scattering KW - Engineering applications KW - Institut Laue Langevin PY - 2019 AN - OPUS4-48396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - X-ray Absorption and Refraction techniques for characterization and non-destructive-testing of materials N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread equally holds for industrial and academic research and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated. I will show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. Examples of micro-structured inhomogeneous materials will be given, such as Composites, Ceramics, Concrete, and Additively manufactured parts. I will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces. Additionally, I will show how Neutron Diffraction, which is extremely well suited to the study of internal stresses, both residual and under external load, can well be coupled to the microstructural framework gained by CT, allowing understanding the microstructure-property relationships in materials. T2 - ENSAM CY - Paris, France DA - 28.11.2019 KW - Additive Manufacturing KW - Computed Tomography KW - Neutron Diffraction KW - X-ray refraction techniques KW - Composites PY - 2019 AN - OPUS4-49927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Characterization of Additive Manufacturing Materials at BAM N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread equally holds for industrial and academic research and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated. I will show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. Examples of micro-structured inhomogeneous materials will be given, such as Composites, Ceramics, Concrete, and Additively manufactured parts. I will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces. Additionally, I will show how Neutron Diffraction, which is extremely well suited to the study of internal stresses, both residual and under external load, can well be coupled to the microstructural framework gained by CT, allowing understanding the microstructure-property relationships in materials. Finally, I will show that BAM is very active in standardization and certification, including production of Reference Materials and Methods. T2 - Skoltech Determination of the microscopic residual stress CY - Moscow, Russia DA - 20.11.2019 KW - Additive Manufacturing KW - Computed Tomography KW - Neutron Diffraction KW - X-ray refraction techniques KW - Composites PY - 2019 AN - OPUS4-49929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Evans, Alexander T1 - Avoid living dangerously: non-destructive characterization of AM parts from powder to end-of-life N2 - The freeform and the revolutionary design possibilities offered by additive manufacturing have skyrocketed the amount of optimization studies in the realm of engineering, and metallic additive manufactured parts are becoming a reality in industry. Not surprisingly, this has not been paralleled by a similar enthusiastic wave in the realm of materials science, and still very little is known about AM materials properties. This has the consequence that, typically, conventional materials properties are still used in design and even in simulations. lt is necessary to dig a lot deeper than at present, in order to understand these new materials classes, and in particular their microstructure and their intemal stresses, largely different from their cast or wrought companions. T2 - ISAM Konferenz 2019 CY - Dresden, Germany DA - 29.01.2019 KW - Computed Tomography KW - Microstructure KW - Metals KW - Additive Manufacturing PY - 2019 AN - OPUS4-47331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brunner-Schwer, C. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Laser-Plasma-Hybrid-Cladding: Possibilities in the combination of arc and laser for deposition welding N2 - Plasma-Transferred-Arc (PTA) welding is a process that enables high deposition rates, but also causes increased thermal 9 load on the component. Laser based Direct Energy Deposition (DED) welding, on the other hand, achieves a high level of 10 precision and thus comparatively low deposition rates, which can lead to high processing costs. Combining laser and arc 11 energy aims to exploit the respective advantages of both technologies. 12 In this study, different possibilities of this process combination are presented using a PTA system and a 2 kW disk laser. 13 This includes the combination in a common process zone as a highspeed plasma laser cladding technology (HPLC), which 14 achieves process speeds of 10 m/min. Besides that it is being examined whether a pre-running plasma arc can be used to 15 coat difficult-to-weld rail steel with a carbon content of 0.8 % due to a preheating effect. Furthermore, a smoothing of the 16 coating by a plasma arc following the laser is investigated. T2 - LiM 2019 CY - Aachen, Germany DA - 25.06.2019 KW - Plasma-Transferred-Arc KW - Direct Energy Deposition KW - Highspeed plasma KW - Laser cladding KW - Deposition welding PY - 2019 AN - OPUS4-49247 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Analytical opportunities & Challenges in (ocean) microplastics N2 - An overview about the analytical opportunities and challenges in microplastic detection is given. T2 - ISO TC61/ Annual bioplastics & ocean microplastics symposium CY - Chengdu, People's Republic of China DA - 29.09.2019 KW - Harmonisation KW - Microplastics KW - TED-GC-MS PY - 2019 AN - OPUS4-50000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Analytic of microplastics in environmental samples N2 - An overview about the existing possibilities for mircoplastic analysis is given. T2 - 2nd International Symposium on Microplastics CY - Seoul, Korea DA - 02.12.2019 KW - Harmonisation KW - Microplastics KW - TED-GC-MS PY - 2019 AN - OPUS4-50003 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brandt, Guido T1 - Wear behaviour of zirconia in hot steam N2 - Self-mated magnesia stabilized zirconia (Mg-PSZ) ceramic sliding couples have been investigated at 100 N load (P0max= 1324 MPa) in oscillating sliding conditions in different humidity conditions in air and in hot steam. Temperatures have been varied up to 400 °C and pressures up to 6 bars. The results show that the wear behavior of MgO-ZrO2 under high Hertzian contact pressures is strongly dependent on temperature and is similar for both dry oscillating and oscillating in hot steam. However, although the evolution in wear rates on temperature is similar and the wear rates of MgO-ZrO2 plunged above 300 °C in hot steam and air by nearly three orders of magnitude, SEM micrographs revealed in hot steam at 400 °C smooth wear tracks. In contrast, hot steam enhanced the tribochemistry of self-mated alumina couples and reduced wear rates. Hot steam decreased the coefficients of friction of MgO-ZrO2 with increasing temperature, but not the wear rates. T2 - 22nd International Conference on Wear of Materials CY - Miami, Florida, USA DA - 14.04.2019 KW - Hot steam KW - Zirconia KW - Friction KW - Wear KW - Tribofilm KW - Raman spectroscopy PY - 2019 AN - OPUS4-47872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - A survey of surface functionalization through laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past few years significantly increasing research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animal integuments, the tailoring of surface colonization by bacterial biofilms, the advancement of medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - Seminar, ALPhANOV - Centre Technologique Optique et Lasers CY - Talence, France DA - 07.06.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Surface functionalization KW - Applications KW - Femtosecond laser PY - 2019 AN - OPUS4-48199 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg T1 - Femtosecond laser-induced periodic surface structures: from light localization to applications N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - International Conference on Advanced Laser Technologies (ALT'19) CY - Prague, Czech Republic DA - 15.09.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser KW - Surface functionalization KW - Electromagnetic scattering PY - 2019 AN - OPUS4-49098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures: from nanoscaled light localization to applications N2 - In this contribution the current state in the field of Laser-Induced Periodic Surface Structures (LIPSS) is reviewed. This includes the mechanisms of formation and current applications, particularly the colorization of technical surfaces, the control of surface wetting properties, the tailoring of surface colonization by bacterial biofilms, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - PHOTONICA 2019 - The Seventh International School and Conference on Photonics CY - Belgrade, Serbia DA - 26.08.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Surface functionalization PY - 2019 UR - http://www.photonica.ac.rs/docs/PHOTONICA2019-Book_of_abstracts.pdf AN - OPUS4-48836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Höhm, S. A1 - Derrien, Thibault J.-Y. A1 - Krüger, Jörg T1 - Laser-induced periodic surface nanostructures N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced in a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers and show a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - International Symposium “Fundamentals of Laser Assisted Micro- and Nanotechnologies” (FLAMN-19) CY - St. Petersburg, Russia DA - 30.06.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser KW - Surface functionalization KW - Ultrafast scattering PY - 2019 AN - OPUS4-48420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg T1 - Quo vadis LIPSS? – Applications of Laser-Induced Periodic Surface Structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past years significantly increasing industrial and research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current trends and applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animals, the tailoring of surface colonization by bacterial biofilms, the advancement of leadless medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - 11. Mittweidaer Lasertagung CY - Mittweida, Germany DA - 13.11.2019 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Applications PY - 2019 AN - OPUS4-49655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Krüger, Jörg T1 - Quo vadis LIPSS? – Recent developments in theoretical modelling and technical applications N2 - This presentation reviews current and expected developments in the field of laser-induced periodic surface structures (LIPSS, ripples). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized radiation. LIPSS are formed in a “self-ordered” way and are often accompanying laser material processing applications. The structures can be produced in a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their spatial periods typically range from several micrometers down to less than 100 nanometers, exhibiting a clear correlation with the polarization direction of the laser radiation used. Various types of LIPSS have been classified, relevant control parameters were identified, and material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Special attention will be paid to a comparison of the currently available formation theories for LIPSS with a discussion of their respective strengths and weaknesses. Currrently explored applications featuring surface functionalization in the fields of optics, surface wetting, medicine, and tribology will be discussed. T2 - 9th International LIPSS Workshop CY - Ljubljana, Slovenia DA - 26.09.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Femtosecond laser ablation KW - Modelling KW - Applications PY - 2019 AN - OPUS4-49708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - Seminar CY - Laser-Laboratorium Göttingen e.V., Germany DA - 18.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Electromagnetic radiation KW - Applications KW - Femtosecond laser ablation PY - 2019 AN - OPUS4-49689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Pentzien, Simone A1 - Krüger, Jörg T1 - X-Ray Emission during Laser Processing with Ultrashort Laser Pulses N2 - Ultrashort laser pulse micromachining features a high precision. By increasing the repetition rate of the applied laser to several 100 kHz, laser processing becomes quick and cost-effective and make this method attractive for industrial applications. Upon exceeding a critical laser intensity, hard X-ray radiation is generated as a side effect. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose becomes significant for high-repetition-rate laser systems so that radiation safety must be considered. T2 - 5th UKP-Workshop: Ultrafast Laser Technology CY - Aachen, Germany DA - 10.04.2019 KW - Laser-induced X-ray emission KW - Radiation protection KW - Ultrashort laser material interaction PY - 2019 AN - OPUS4-47788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Wirth, Thomas A1 - Florian, Camilo A1 - Sturm, Heinz A1 - Spaltmann, Dirk A1 - Krüger, Jörg T1 - Chemical effects during the formation of femtosecond laser-induced periodic surface structures N2 - The processing of laser-induced periodic surface structures (LIPSS, ripples) on metals and semiconductors in ambient air is usually accompanied by superficial oxidation effects – a fact that is widely neglected in the current literature. In this contribution, chemical, structural, and mechanical alterations in the formation of femtosecond LIPSS are characterized by a variety of surface analytical techniques, including energy dispersive X-ray analyses (EDX), X-ray photoelectron spectroscopy (XPS), micro Raman spectroscopy (µ-RS), and depth-profiling Auger electron microscopy (AEM). Alternative routes of electrochemical and thermal oxidation allow to qualify the relevance of superficial oxidation effects on the tribological performance in oil lubricated reciprocating sliding tribological tests (RSTT). It is revealed that the fs-laser processing of near-wavelength sized LIPSS on metals leads to the formation of a few hundreds of nanometers thick graded oxide layers, consisting mainly of amorphous oxides. Regardless of reduced hardness and limited thickness, this nanostructured surface layer efficiently prevents a direct metal-to-metal contact in the RSTT and may also act as an anchor layer for specific wear-reducing additives contained in the used engine oil. T2 - EMRS Spring Meeting 2019, Symposium V “Laser interactions with materials: from fundamentals to applications" CY - Nice, France DA - 27.05.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Oxidation KW - Tribology PY - 2019 AN - OPUS4-48127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -