Eigenschaften und Anwendungen von Chemisch Nickel‐Dispersionsschichten

Properties and applications of electroless nickel composite coatings This paper discusses the variety of composite electroless coatings used in different industrial applications. The inclusion of particulate matter within electroless nickel deposits can add entirely new properties to the plated layer. Composites with hard particles like diamond, silicon carbide and boron carbide provide greater wear resistance and the possibility for adjustable friction properties. Composite electroless nickel with diamond or ceramics has found wide applications in the textile, automotive and mechanical engineering industry. Friction joints in automotive engines constitute an important field of application for diamond coatings. Modern internal combustion engine designs require that the crankshaft and camshaft be fitted at a specific relative angle. In order to establish the correct angle during assembly and maintain it over the life of the engine, axial press‐fit joints in combination with centrally located retention bolts are employed. Failure of either the joints or the bolts can result in serious damage to the engine. The torque transfer ability of these engine components can be significantly increased by incorporating a friction foil that is diamond‐coated on both sides. Composite coatings with coarser diamond particles can be used for the coating of precision tools in the semiconductor industry. Enhanced lubricity can be achieved by incorporating solid lubricants in electroless nickel deposits. Composite coatings with PTFE or PFA offers non‐stick surfaces with antiadhesive properties and good resistance against adhesive wear. Because of the temperature and softness limitations these coatings are best suited for lower temperature and light loading applications. Electroless nickel boron nitride coatings can withstand temperatures up to 600 °C. This coating reduces coefficient of friction and wear in dynamic applications. A further application is the coating of molds for rubber and plastic components.     

Neue Methoden zur Beurteilung der Betriebsfestigkeit im Fahrzeugauslegungs‐ und ‐absicherungsprozess

Advanced durability evaluation in vehicle design and validation process The modern process of evaluation and validation conducted in the automotive industry uses experimental, metrological, and calculation‐based methods. Offering various examples, the present paper describes new developments in the determination and evaluation of operating strength, particularly in terms of virtual methods and their application in practice. The first point considered is the virtual determination of load data, the second is the improvement of calculated fatigue life. Two current examples in the development of methods are presented in this context: The first example examines the inhomogeneity of materials in calculating aluminium castings. The second example describes the approach taken in the configuration of components made of short‐fibre‐reinforced polymers, applying a new method of calculation.     

Potenziale von ionischen Flüssigkeiten als Elektrolyte in der Galvanotechnik

Application potentials of ionic liquids based electrolytes in electroplating Electroplating is essential for a variety of industries including, electronics, sensors, optics, automotive and aerospace. The electroplating industry, which dates back well over 100 years, is based solely on aqueous electrolytes. The advancement of new materials and increasing requirements to functionalized metallic surfaces however constricts the application potentials of classical electrolyte systems. New application fields for the electroplating industry could arise by further developments and optimisation of aprotic electrolytes based on ionic liquids. In this article a short insight will be presented to possibly applications of ionic liquids as metal electrolytes for surface technology and electroplating. After a short introduction to ionic liquids an overview will be given to relevant physical‐chemical properties of ionic liquids, like metal solubility, viscosity and electrical conductivity. In addition current experimental results from our laboratory to the metal deposition of aluminium, cobalt and palladium will be presented and discussed. The main focus was set in the choice of different electrolyte systems, deposition parameters and achieved surface morphology of the produced metal deposits.     

Characterization of beryllium foil produced by hot rolling

Beryllium foil is important for a number of aerospace applications including honeycomb structures and metal-matrix composites. In this study, a method of producjng beryllium foil directly from powder or flake is demonstrated. A variety of foils were produced in the thickness range 90–300 m, free from defects such as pinholes and excessive surface roughness, and exhibiting sufficient formability for honeycomb manufacture. Foil produced directly from powder or flake exhibits crystallographic texture, microstructure, and formability equivalent to foil produced from more massive precursors.     

Werkstoffverhalten unter zügiger elastischer Beanspruchung

Material properties by continuous elastic straining Within the scope of a common research project of the steel and automotive industry, 20 sheet steels have been investigated to obtain input data for FE‐analysis. In detail, characteristical elastic, plastic and fatique values were determined by several testing institutes for a period of 3 years. Knowledge of dependency of Young’s modulus from temperature and orientation is important for spring back at the press shop and stiffness of parts for automotive. Young’s modulus was determined by tensile tests in delivered state, after prestraining, heat treatment at room temperature and –40 °C and 100 °C. Young’s modulus is dependent from the orientation to rolling direction and can be classified in groups. Young’s modulus of ferritic steels is decreased about 10 % by prestraining of 2 % but recovered after annealing at 170 °C. Temperature dependency well known from non destructive tests are confirmed.     

Mounting stripper foils on forks for maximum lifetime

While research and development continue to produce forms of carbon for longer lasting stripper foils, relatively little attention has been paid to other factors that affect their survival in use. It becomes apparent that the form of carbon is only part of the issue. Specific mounting methods increase the lifetimes of carbon stripper foils. These methods are determined in part by the specific use and carbon type for a foil. With careful handling, appropriate adhesive, and slack mounting, premature breakage can be avoided. Foil lifetimes are then primarily affected by less easily controlled factors such as high-temperature expansion, shrinkage and evaporation.     

Polymere Nanoverbundwerkstoffe: Chancen,Risiken und Potenzial zur Verbesserung der mechanischen und physikalischen Eigenschaften

Polymer Nanocomposites: chances, risks and potential to improve the mechanical and physical properties The development of nano‐particle reinforced polymer composites is presently seen as one of the most promising approaches of materials for future engineering applications. The unique properties of at least some types of the nano‐particles (e.g., Carbon Nanotubes or Carbon Black) and the possibility of combining them with conventional materials and reinforcements (e.g., carbon‐, glass‐ or aramid‐fibres), has led to an intense research in the field of nanocomposites. Especially Carbon Nanotubes have shown a high potential for an improvement of the properties of polymers. Besides an increase in the electrical conductivity even at an extremely low nanotube content the improvement of the mechanical properties is of special interest. The exceptionally high aspect ratio in combination with a low density and a high strength and stiffness make the carbon nanotubes a most interesting candidate for a reinforcement of polymeric materials. The electrical, mechanical and thermal properties of Carbon Nanotubes open up new perspectives also for their use as multifunctional materials, e.g. conductive polymers with improved mechanical performance. The problem, however, is to transfer the interesting potential regarding the mechanical, thermal and electrical properties to the polymer. Two main issues have to be addressed for a significant improvement of the properties of polymers by adding Carbon Nanotubes: the interfacial bonding and, especially also, a proper dispersion of the individual Carbon Nanotubes in the polymeric matrix.     

Zur Plausibilität der Methode der Zugdreiecke

On the Plausibility of the Method of Tensile Triangles (MTT) The shape optimization of components, developed in Forschungszentrum Karlsruhe after the design rules of nature [1] has during the last 15 years very well spread and proven itself in industry, especially in automotive engineering. The limits for using the CAO‐method (Computer Aided Optimization) are more or less of economical nature. In this paper the plausibility for a new pure graphical method is shown, which works without any FEM or optimization software.     

New 2-D dosimetric technique for radiotherapy based on planar thermoluminescent detectors

At the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ) in Kraków, a two-dimensional (2-D) thermoluminescence (TL) dosimetry system was developed within the MAESTRO (Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology) 6 Framework Programme and tested by evaluating 2-D dose distributions around radioactive sources. A thermoluminescent detector (TLD) foil was developed, of thickness 0.3 mm and diameter 60 mm, containing a mixture of highly sensitive LiF:Mg,Cu,P powder and Ethylene TetraFluoroEthylene (ETFE) polymer. Foil detectors were irradiated with (226)Ra brachytherapy sources and a (90)Sr/(90)Y source. 2-D dose distributions were evaluated using a prototype planar (diameter 60 mm) reader, equipped with a 12 bit Charge Coupled Devices (CCD) PCO AG camera, with a resolution of 640 x 480 pixels. The new detectors, showing a spatial resolution better than 0.5 mm and a measurable dose range typical for radiotherapy, can find many applications in clinical dosimetry. Another technology applicable to clinical dosimetry, also developed at IFJ, is the Si microstrip detector of size 95 x 95 mm(2), which may be used to evaluate the dose distribution with a spatial resolution of 120 microm along one direction, in real-time mode. The microstrip and TLD technology will be further improved, especially to develop detectors of larger area, and to make them applicable to some advanced radiotherapy modalities, such as intensity modulated radiotherapy (IMRT) or proton radiotherapy.     

Dual phase versus CMn strip steels: comparison of quasi-static and dynamic connection properties for road safety barriers

Abstract

The use of high strength steel grades in automotive applications has been widely recorded. This is due largely to vehicle weight reduction programmes as well as increases in vehicle crash safety legislation. This represents the steel industry’s response to the challenge that vehicle components manufactured from steel could get replaced with alternative materials, such as aluminium and polymers. Consequently, new high strength steel grades have been developed to offer credible alternatives. Recently, the UK government has released a new specification, BS EN 1317-1-2-3-4: Road Restraint Systems, to which all new safety barrier designs have to comply. However, much of this development and subsequent usage has been targeted at automotive manufacturers. Road safety barrier technology has not evolved in the same way when compared to vehicle technology. Therefore, a study has been undertaken to assess the outcome of using some of these novel high strength steel grades for the manufacture of road safety barrier components. Quasi-static and dynamic tensile testing at different velocities was undertaken. Representative connection coupons were used to understand the energy absorbing properties of a dual phase steel grade when compared to the current CMn steel grade. The present study presents some initial results as to the increased performance that could be gained from utilising new high strength steel grades for the production of road safety barrier systems.     

Refrigeration and the world's food supply — especially in developing countries

The reason for starvation today is poverty. Refrigeration can help the developing countries to export high value products. This helps to improve the economical situation and their buying power. Refrigeration can also help to reduce waste. Primitive distribution systems using refrigeration can be used at an early stage but the infrastructure is the limiting factor for introduction of modern transport equipment. Appropriate refrigeration technology is required, and the IIR should promote this by, for example, introducing an award for good proposals.     

Energy Conservation Ordinance 2014 – On the way to the nearly zero energy building / EnEV 2014 – auf dem Weg zum Niedrigstenergiegebäude

The tightening of the Energy Conservation Ordinance in 2016 provides the first step toward the introduction of nearly zero energy buildings. The level of performance for residential buildings after 2020 will most likely attain an energy quality close to the primary energy consumption of the KfW Efficiency House 55 today, at least regarding performance. The following report describes the requirements methodology of the Energy Conservation Ordinance 2014, including the KfW promotion, and provides calculation examples to clarify the issues.     

Organische Polymere als funktionelle Werkstoffe für chemische Sensoren

Organic polymers as functional materials for chemical sensors The function of many chemical sensors for measurements in liquids and in gases with ambient temperature is based on the combination of a transducer with organic membranes. These membrans determine essential sensor properties as selectivity, sensitivity and response characteristics. In addition they protect the detection system against external influences. Therefore the selection and synthesis of polymer membranes are an essential constituent of the sensor investigation and sensor development. Electrical, optical and biological properties of the polymers are important in this case. A survey of the materials used in the remote sensing is given. Of special interest to the sensor investigation are in last time intrinsic conducting polymers (ILP) whose properties opened new possibilities of the sensor development. With the help of an electrochemical pH glass electrode with inner solid contact it is shown that polypyrrole can be used as a material for a long‐lived inner solid contact and as substitute for inner secondary reference electrode. Practice tests confirm the suitability of this polymer material. Aspects of the transport mechanism of electrical charges through the boundary surface conducting polymer | glass are discussed.     

Preparation, characterization, and electrochromic properties of novel Co(II)-bis-2,2’:6’,2”-terpyridine metallo-supramolecular polymers

A rich variety of novel ditopic bis-terpyridines, by symmetric and unsymmetric introduction of functional groups in the pyridine rings, as well as tuning the spacers for bridging the two terpyridine moieties, is described. These bis-terpyridines are useful ligands for developing new metallo-supramolecular materials with novel functions, as well as for investigating the structure-property relationships. In order to investigate the structural factors of bis-terpyridine based metallo-supramolecular materials, such as the functional groups in the ring periphery of the ligands and the spacers between the two terpyridine coordination components, several different types of Co^II-bis-terpyridine supramolecular polymers were prepared from various bis-terpyridine functional modules and Co(OAc)₂. The absorption and the electrochemical behavior of these new supramolecular polymers were studied by UV/Vis spectroscopy and differential pulse voltammetry (DPV), respectively. The results showed that the introduction of electron donating groups at the pyridine ring affects remarkably the charge transfer and electrochemical properties of the coordination polymers. In addition, the electrochromic properties of the coordination polymers were also studied. Significant color change and high reversibility were observed from these polymers.     

Innovative façade technology using masonry – Solid construction 2.0 / Innovative Fassadentechnik mit Mauerwerk – massiv construction 2.0

This article illustrates the solid building envelope both as an integral system and in terms of its potential for additive manufacturing. The Façade Research Group at the TU Delft works on the building envelope, investigating strategic and process support for development and planning processes and renovation technologies, as well as functionally integrated building envelopes. The Institute of Structural Mechanics and Design at the TU Darmstadt undertakes research and development in the areas of materials technologies (glass, polymers) and additive manufacturing as they relate to building structure.     

Herstellung und Umformverhalten austenitischer Polymerkernsandwichverbunde

Production and forming behaviour of austenitic steel sandwich composites with a polymer core layer Three‐layered symmetrical sandwich combines offer a great lightweight construction potential due to their structural construction and her good recession behavior at simultaneously high strength. By the combinability of the qualities of the combined partners sandwich combines as good solution offer their services if it is about high strength at good resistance in the lightweight construction. Depending on a functional request all sorts of materials, metals, polymer and others, are used as deck and nuclear material. This one is a central problem for the construction, the processing and later use of sandwich systems in comparison with the monolithic materials, terrible forming behaviour of the combined partners with strongly different Youngth Modulus as well as the question of the adhesion of the different material layers. Nowadays the industrial use of such sandwich materials is still limited. In the context of the project “Untersuchungen zur Kompatibilisierungsmethode ”Umformen“ für unterschiedliche Metall ‐ Nichtmetall – Systeme” promoted by the DFG three layered Sandwich materials were manufactured and analyzed for their characteristics concerning the adhesive strength of the sandwich partners and the forming behaviour. The task existed in the development, the production and investigation of new sandwich materials, which can be adapted to special requirements regarding their functional characteristics. Only the combined view of the material and constructional components leads to system‐oriented materials, construction units, concepts and structures. On the basis of an industrially manufacturing process an adapted press‐joining process for sandwich materials was developed. At the beginning of the project polymer foils were used as core materials, then in th developed pres‐joining process different polymers granules were used as core material. Thereby fiber‐reinforced PA and PP granules were used. As skin layers high‐grade steel sheets of the quality 1,4404 and aluminum plates AlMg3 were used. Depending upon manufacturing processes for the polymer foil an epoxy resin adhesive was used and for the polymer granules three different adhesion agents were used. A reproducible manufacturing could be proven by the angle peeling test. The stretching and deep‐drawing characteristics of the sandwich materials as a function of the core layers could be pointed out in the Erichsen‐Test and in first deep‐drawing investigations. So the Youngth Modulus in the comparison to the polymer foil could be increased by fiber‐reinforced polymer granules. It was possible to change the deep‐drawing behaviour clearly.     

Non-contact strain measurement using metal foil gauges with the application of the laser speckle method

This paper presents a new method to measure cyclic strain with no contact using metal foil gauges assisted by the laser speckle method. When aluminium foil is pasted on a specimen and the specimen is loaded cyclically, slip bands are produced on the foil surface. There is a fixed relation between density of the slip bands and the strain amplitude or loading cycles depending on the foil material. Thus the fatigue strain of the base metal can be estimated by observing the surface change of the metal foil by the slip bands at a constant number of loading cycles. The method presented in this paper is intended to make a non-contacting strain measurement by the application of the laser speckle technique for the detection of the surface change. This method is based on observation of the changes in a laser speckle pattern depending on the surface roughness and surface property changes of the foil caused by fatigue. The laser speckle pattern can be analysed automatically and quantitatively using an image processing system.     

Innovatives Elektronenstrahlschweißen hochschmelzender Metalle

Innovative electron‐beam welding of high‐melting metals Since its establishment as nuclear research plant Juelich in the year 1956, the research centre Juelich (FZJ) is concerned with the material processing of special metals. Among those are, above all, the high‐melting refractory metals niobium, molybdenum and tungsten. Electron beam welding has always been considered to be an innovative special welding method; in the FZJ, electron beam welding has, moreover, always been adapted to the increasing demands made by research partners and involved manufacturing and design sectors. From the manual equipment technology right up to highly modern multi‐beam technique, the technically feasible for fundamental research has, this way, always been realised.     

Klebtechnik – multifunktionales Fügen für den nachhaltigen Werkstoffeinsatz im 21. Jahrhundert

Adhesive bonding technology – multifunctional joining for the sustainable use of materials in the 21^st century Adhesive bonding meets the key requirements for the sustainable joining technology of the 21^st Century: different materials can be assembled with integrated additional functions in a weight saving manner. The review paper outlines introductory the origin and the commercial relevance of adhesive bonding technology. Methods of surface treatment and the meaning of adhesion and cohesion are discussed. The classification of the adhesives occurs according to the setting mechanism. The right selection is explained. The comparison with other joining technologies is important for the assessment of adhesive bonding. The geometric design of the joint is based on construction guidelines: one should avoid stress peaks and maximize the glue area. Simple notes for the strength calculation make dimensioning easier. Materials testing in adhesive bonding engineering is described. The thick‐adherend tensile shear test is suited for the in situ determination of mechanical characteristics. Applications of adhesive bonding in aviation and aerospace and transportation are presented. Besides these traditional industries, new markets in sectors like electronics and medicine are opened up. Due to high strength and deformability, chemically curing products solve demanding tasks in adhesive bonding and sealing technology.