TY - CONF A1 - Reetz, U. A1 - Lerche, D. A1 - Hielscher-Hofinger, Stefan A1 - Kubitzki, Jan A1 - Beck, Uwe T1 - Load- and path-controlled determination of bonding strength of butt joints - Comparison between tensile testing machine and centrifuge technology N2 - The round robin test proves that the CAT-Technology provides statistically indistinguishable test results compared to TTM. A supplement to DIN EN 15870 taking into account CAT-Technology (with reference to equivalent increases of load and displacement) as second normative test method appears to make sense. A presentation of a revision proposal at CEN TC 193 has been introduced with the decision to conduct a survey using the unchanged German revision proposal. T2 - EURADH 2021 - 13 th European Adhesion Conference CY - Online meeting DA - 11.10.2021 KW - CAT – Technology KW - Tensile testing machine (TTM) KW - Round robin test KW - Validation PY - 2021 AN - OPUS4-53948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frisch, M. A1 - Raza, M. H. A1 - Ye, M.-Y. A1 - Sachse, René A1 - Paul, B. A1 - Gunder, R. A1 - Pinna, N. A1 - Kraehnert, R. T1 - ALD-coated mesoporous iridium-titanium mixed oxides: Maximizing iridium utilization for an outstanding OER performance N2 - With the increasing production of renewable energy and concomitant depletion of fossil resources, the demand for efficient water splitting electrocatalysts continues to grow. Iridium (Ir) and iridium oxides (IrOₓ) are currently the most promising candidates for an efficient oxygen evolution reaction (OER) in acidic medium, which remains the bottleneck in water electrolysis. Yet, the extremely high costs for Ir hamper a widespread production of hydrogen (H₂) on an industrial scale. Herein, the authors report a concept for the synthesis of electrode coatings with template-controlled mesoporosity surface-modified with highly active Ir species. The improved utilization of noble metal species relies on the synthesis of soft-templated metal oxide supports and a subsequent shape-conformal deposition of Ir species via atomic layer deposition (ALD) at two different reaction temperatures. The study reveals that a minimum Ir content in the mesoporous titania-based support is mandatory to provide a sufficient electrical bulk conductivity. After ALD, a significantly enhanced OER activity results in dependency of the ALD cycle number and temperature. The most active developed electrocatalyst film achieves an outstanding mass-specific activity of 2622 mA mg(Ir)⁻¹ at 1.60 V(RHE) in a rotating-disc electrode (RDE) setup at 25 °C using 0.5 m H₂SO₄ as a supporting electrolyte. KW - Acidic oxygen evolution reaction KW - Atomic layer deposition KW - Electrocatalysis KW - Iridium oxide KW - Soft-templated mesoporous films PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542651 DO - https://doi.org/10.1002/admi.202102035 SN - 2196-7350 SP - 1 EP - 11 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Julia T1 - In situ Atomic Force Microscopy (AFM) studies of corrosion processes on thin film coated AA2024-T3 aluminium alloy surfaces N2 - The performance of functional coatings relies strongly on the stability of the polymer-metal interface. The increasing utilization of multi-material structures in the automotive and aerospace industry necessitates a fundamental understanding of the processes leading to interface degradation for the development of novel strategies to increase corrosion and delamination resistance. The aim of this project is to investigate the corrosion processes at the buried interface of thin film coated aluminium alloy AA2024-T3 under corrosive and coupled corrosive-mechanical load. A spin coating procedure was developed to synthesize epoxy-like coatings and their nanofiller loaded composites with controlled thickness by layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Our results indicate that the incorporation of graphene into the epoxy-based coatings leads to the improvement of mechanical and barrier properties. Furthermore, the functional groups play important roles in the interfacial bonding between polymer matrix and the nanofillers. Atomic force microscopy (AFM) results indicate very homogeneous and dense films with a thickness of ~25 nm per bi-layer and the successful integration of the nanofillers into the composite coatings. Ellipsometry measurements of film thickness verified a proportional film growth with the number of deposited layers. The degradation and delamination behavior of the coating systems was characterized by means of in situ AFM corrosion experiments. Complementary energy dispersive X-ray spectroscopy (EDX) analysis was used to correlate the corrosion and delamination behavior with the different intermetallic particle chemistries and distributions. The presentation will summarize our results on the effect of coating composition and build-up on the local corrosion processes on thin film covered AA2024-T3 aluminium alloys. T2 - Eurocorr 2021 CY - Online meeting DA - 20.09.2021 KW - In situ AFM KW - Corrosion KW - Thin epoxy-based films PY - 2021 AN - OPUS4-54053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Mitzkus, Anja A1 - Sahre, Mario A1 - Lange, Thorid A1 - Weise, Matthias A1 - Bartholmai, Matthias A1 - Schukar, Vivien A1 - Basedau, Frank A1 - Hofman, Detlef A1 - Köppe, Enrico T1 - From on line sensor validation to in-situ monitoring of layer growth: coatings around fibre bragg gratings N2 - The lack of on-line validation procedures for structure-embedded fiber-optical strain sensors, in particular fiber-Bragg-gratings (FBG), resulted in limited applications in structural health monitoring (SHM). Degradation under service conditions and ageing as a result of climatic influences or delamination under load were unsolved Validation issues. This could be overcome by means of an auto-diagnosis procedure based on FBG-sensors coated by electrochemical deposition (ECD) with a magnetostrictive NiFe-coating on top of an adhesive Cu/Cr adhesive layer deposited by physical vapour deposition (PVD) around the FBG strain sensor. This allows at any time under Service a validation of sensor functionality, stability, and reliability. For this purpose, a magnetic strain-proportional reference field is introduced. The optical read-out is realized by the measurement of the Bragg-wavelength shift. The ratio of resulting strain and exciting magnetic reference field should be constant given that the sensor is in proper function. In principle, the magnetostrictive coating around the FBG should also work as on-line magnetic field sensor and other applications in material science. One of these applications is the in-situ monitoring of ECD processes as the deposition of the ECD NiFe-layer on the FBG revealed. Challenges are the monitoring of temperature, deposition stages/thickness, and resulting mechanical stress under given plating conditions. Monitoring problems can be solved by applying a pre-coated FBG to the electrolytic process as the shift of the Bragg wavelength is affected by both the temperature of the electrolyte near the substrate and the stress formation in the growing layer. The experimental FBG set-up and the quantitative determination of temperature- and stress-related strain are described for a nickeliron electrolyte. The in-situ measurement of Bragg wavelength shifts of a pre-coated FBG during electrochemical deposition allows a detailed analysis of stress states due to changes in the growth morphology of the layer. The separation of mechanical and thermal contributions to this shift provides information on the individual Deposition processes in terms of a process fingerprint. T2 - ICMCTF 2021 San Diego/on-line CY - Online meeting DA - 28.04.2021 KW - Fiber- Bragg-gratings (FBG) KW - Physical vapour deposition (PVD) KW - Electrochemical deposition (ECD) KW - Magnetostrictive coating KW - ECD NiFe-layer PY - 2021 AN - OPUS4-52898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Windhövel, U. A1 - Hielscher-Hofinger, Stefan A1 - Lerche, D. A1 - Reetz, U. T1 - Proposal for revision of en 15870 „Adhesives determination of tensile strength of butt joints” N2 - The paper addresses the PROPOSAL FOR REVISION OF EN 15870 „ADHESIVES -DETERMINATION OF TENSILE STRENGTH OF BUTT JOINTS” “ and the follow points are discussed in more detail: Adhesives-Determination of tensile strength of butt joints, Introduction of Centrifugal Adhesion Testing, Comparison of Testing Methods. T2 - CEN TC 193 Madrid CY - Online meeting DA - 04.03.2021 KW - Centrifugal Adhesion Testing (CAT) KW - DIN EN ISO/IEC 17025 KW - Adhesives - Determination PY - 2021 AN - OPUS4-52900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Baier, Jennifa A1 - Hidde, Gundula A1 - Sahre, Marion A1 - Weise, Matthias T1 - Particles in PVD-coatings: Imperfection or functional add-on feature? N2 - The application of PVD-coatings ranges from mechanical engineering, i.e. thicker tribological coatings, to precision optics, i.e. thinner optical coatings. For physical vapor deposition (PVD) technologies such as evaporation, sputtering, ion beam assisted/driven deposition, vacuum is a prerequisite for two reasons: at first process-related ones (evaporation source, plasma discharge, and mean free path) and at second coating-related ones (pure, perfect, and dense films). Usually, the goal is a homogenous coating of defined stoichiometry and micro-structure without any imperfection. However, the implementation of micro- or nano-particles may occur accidentally or delibe-rately. Independent of the particle origin, there are two fundamental rules regarding coating functionality: at first, the larger the particle diameter to coating thickness ratio the more affected the functionality of the coating, and at second, the larger the material contrast in terms of the functional feature of interest the more affected the coating performance. Hence, embedded particles have to be avoided for the majority of thin films by all means. The unintended implementation of particles usually results in a malfunction of the coating from the beginning or is at least considered as a weak point of the coating creating a time-dependent defect under service conditions. The intended implementation of particles on surfaces and in coatings may create add-on features, topographic ones and functional ones, however, the facts mentioned hold true. Examples of particle-initiated coating defects are demonstrated in dependence on the origin and the field of application. Strategies for deliberate attachment/embedding of particles on surfaces/in coatings are discussed regarding process compatibility and coating integrity. For industrial applications, both the validation of process compatibility of particle injection and the plasma resistance of particles under vacuum and plasma conditions have to be confirmed. Further points of interest are the homogeneity of particle distribution and the avoidance of particle agglomeration which is still a crucial point for dry dispersed particles. So far, technical applications are limited to PVD hybrid coatings, plasma dispersion coatings are still a challenge except for applications where homogeneity is not required as in case of product authentication. T2 - ICMCTF 2018, International Conference on Metallurgical Coatings and Thin Films CY - San Diego, CA, USA DA - 23.04.2018 KW - PVD-coatings KW - PVD-processes KW - Unintended particle generation KW - Particles as imperfections KW - Deliberate particle implementation KW - Particles as add-on features PY - 2018 AN - OPUS4-44973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René T1 - Towards hydrogen economy: correlative ex-situ ellipsometric analysis and operando investigation during oxygen evolution reaction of mesoporous iridium oxides films N2 - In the face of rising energy demand and the impending climate change the development of a sustainable, fossil-free fuel and chemical production is of global importance. One possible goal is the development of electrochemical conversion processes using catalysts. Porous materials play an important role in such energy applications. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physico-chemical properties. However, the complex morphology of such catalysts constitutes a challenge even for modern analytical techniques. Spectroscopic ellipsometry (SE) is a versatile method for studying material properties by using appropriate models (e.g. film thickness, optical and electronic properties). The fact that the material properties cannot be taken directly from the measured spectra, the developed models have to be validated. In a first step, the model for the ellipsometric fit studies of a calcination series of mesoporous iridium oxide films (300 – 600 °C) was investigated and validated with respect to their material properties. Moreover, the electronic structures of the catalysts reveal a direct correlation with electrochemical activities. The development of an environmental cell offers the possibility of investigations under real conditions. This will allow changes in the optical and electronic properties during the electrocatalytic oxygen evolution reaction. T2 - Colloquium Department Seminar 6. CY - BAM, Berlin, Germany DA - 03.03.2020 KW - Hydrogen economy KW - Correlative ex-situ ellipsometric analysis KW - Ellipsometric operando investigation KW - Oxygen evolution reaction KW - Mesoporous iridium oxides films PY - 2020 AN - OPUS4-51215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griepentrog, Michael T1 - Estimation of measurement uncertainty of instrumented indentation testing N2 - Some critical discussion of the state of the art of uncertainty evaluationin Instrumented Indentation Testing IIT Nowadays the Instrumented Indentation Testing (IIT), in the nano range often named as nano indention, is one of the most commonly used methods to determine the mechanical properties of materials in the micro and nano range. This method is already extensive standardized in ISO 14577 part 1-4. In the past, the application of this standard in testing praxis shows that the established values have an excellent precision.If an uncertainty is calculated, the range of values within which the true value is asserted to lie with some level of confidencewill be known. In part 1 of ISO 14577 [1] two methods for evaluation of the uncertainty in IIT are mentioned: Method 1 for determining uncertainty considers only those uncertainties associated with the overall measurement performance of the testing machine with respect to the reference blocks. Method 2calculates a combined uncertainty from individual contributions. These may be grouped into random and systematic uncertainties. Both methods will be described in detail using examples from the dailyexperimental praxis. The comparabilityof both methods will be critically discussed. Finally, it will be showedhow the calculated uncertaintiescan be used for performancetests and product specifications. Acknowledgement This work was performed under the support of the EMPIR project 17NRM05Advancing measurement uncertainty̶ comprehensiveexamples for key international standards References [1] ISO 14577 part 1 (2017) T2 - KLA Nanomechanical Testers User Workshop CY - Langen, Germany DA - 02.05.2019 KW - Instrumented Indentation Testing KW - IIT KW - nanoindentation KW - mechanical properties KW - uncertainty KW - performance test KW - product specification PY - 2019 AN - OPUS4-48141 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Hielscher-Hofinger, Stefan A1 - Hidde, Gundula A1 - Lange, Thorid A1 - Weise, Matthias A1 - Lerche, D. A1 - Rietz, U. T1 - Adhesion of Coatings vs. Strength of Composite Materials – A Review of Applications Evaluated by Centrifugal Adhesion Testing (CAT) N2 - Sufficient adhesion/tensile strength are basic requirements for any coating/composite material. For coatings, adhesive strength in N/mm2 is of Major interest for various applications such as decorative and water-repellent coatings on wood (paints and varnishes), optical coatings on glass and polymers (reflectors and filters), electrical coatings on semiconductors, glass and polymers (conducting and bondable layers), mechanical coatings on metals and polymers (wear-reduction, scratch-resistance) and adhesion-promoting layers. For composite materials, tensile strength in N/mm2 is also a key quantity for carbon fiber reinforced composites (CFC), laminates and adhesive-bonded joints. Centrifugal adhesion testing (CAT) transfers the single-sample tensile test from a tensile or universal testing machine into an analytical centrifuge as multiple-sample test of up to eight test pieces. The one-sided sample support instead of a two-sided sample clamping and the absence of mounting- and testing-correlated shear forces provides fast and reliable results both for adhesive strength and bonding strength by means of bonded test stamps. For bonding strength, the evaluation of failure pattern from microscopic inspection is required in order to determine the failure pattern according to ISO 10365 such as adhesive failure (AF), delamination failure (DF) and cohesive failure (CF). Hence, one test run by CAT-technology provides either statistics or ranking of up to eight samples at once. For adhesive strength of coatings, a variety of examples is discussed such as ALD-Al203 layers as adhesion promoters, evaporated Ag-layers on N-BK7 glass, sputtered Cr- and Al-layers on Borofloat 33 glass, evaporated Au-films on N-BK7 glass and sputtered SiO2 -layers on CR39 Polymer. Provided adhesive or bonding strength are high enough, the substrate or the joining part may also fail. T2 - Special PSE 2020 CY - Online meeting DA - 07.09.2020 KW - Centrifugal adhesion testing (CAT) KW - Adhesive strength KW - Pull-off test KW - Failure pattern KW - Compound strength PY - 2020 AN - OPUS4-51231 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hielscher-Bofinger, Stefan A1 - Beck, Uwe A1 - Lerche, D. A1 - Rietz, U. T1 - Multiple-sample Testing: Adhesive Strength of Coatings and Bonding Strength of Adhesives evaluated by Centrifugal Adhesion Testing (CAT) N2 - The quantitative determination of adhesion and cohesion properties is a key requirement for adhesive-bonded joints and coated components in both R&D and Quality assurance. Because of the huge variety of layer/substrate Systems in terms of materials and large thickness range, adhesion tests display the same diversity as layer/substrate systems. There are only two tensile testing procedures available, that determine adhesive strength in terms of force per area (N/mm²), the single-sample pull-off test in a tensile testing machine and the multiple-sample-test using the Centrifugal Adhesion Testing (CAT) Technology. The CAT Technology is a testing method which uses centrifugal force as tensile testing force in a multiple-sample arrangement within a drum rotor of a Desktop centrifuge. Hence, the adhesive/bonding strength A/B can be determined on a statistical basis under identical testing conditions for up to eight samples. A variety of examples for bonding strength of adhesives, adhesive strength of coatings and compound strength of composite materials is discussed such as metalto-metal and glass-to-metal bonding, sputtered SiO2-layers on CR39 Polymer and carbon fiber reinforced polymer. T2 - Colloquium Department 6. CY - Berlin, BAM, Germany DA - 03.09.2020 KW - Centrifugal Adhesion Testing (CAT) KW - Adhesive strength KW - Bonding strength KW - Composite strength KW - Interlaboratory comparision PY - 2020 AN - OPUS4-51178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -