An analysis of current surface treatments used for electrical devices with a focus on the quality, durability and costs of the technologies. An overview of the surface treatments used in the specified area with a summary of parameters reached today.

Diploma thesis is worked-up as a part of master’s studies of engineering technology M2I – K, analyzing the possible methods of surface treatment of spherical pin, that increase its corrosion resistance. Spherical pin is mounted into several types of chassis components such as joints, control arms, etc. The current situation is inconvenient for manufacturers, insufficient corrosion protection increases the number of complaints and this may be reflected in the number of future orders. Via of suitable surface treatment is to achieve a higher corrosion resistance while maintaining the functional properties of pins used.

This master thesis describes design of suitable surface treatment technology to get component resistant to corrosion of conventional atmosphere. Given component has a shape of pin and is made of construction steel. At the beginning, there is a theoretical study of galvanic zinc coating and galvanic surface treatment in general. Then there is analysis of damaged galvanic zinc surface and its impact of corrosive resistance of that layer with collaboration with company KOZÁK SVITAVY. Corrosive resistance of damaged zinc layer is then compared with corrosive resistance of quality zinc layer. At the end of this thesis is technical and economic evaluation.

La production de masse de cavités accélératrices supraconductrices en régime radiofréquence (SRF) est un réel défi industriel non seulement du fait du nombre croissant de cavité pour les futurs grands projets mais également de par les besoins en terme de fiabilité, reproductibilité et performances demandées très proches des limites physiques du Niobium. De nos jours, XFEL (DESY) et le LHC (CERN) sont les deux accélérateurs les plus importants utilisant la technologie supraconductrice. Des projets accélérateurs encore plus ambitieux, tels que l’ILC (International Linear Collider) et FCC (Future Circular Collider) sont en cours d’étude. Pour de tels projets, il est encore nécessaire d’améliorer les performances et de réduire les coûts de fabrication et d’opération avant d’engager la phase d’industrialisation.Une voie d’amélioration des performances et de réduction des coûts a été étudiée. Ceci consiste à améliorer les procédés de nettoyage des surfaces. En effet, la pollution et les dommages causés à la structure cristalline durant la fabrication d’une cavité supraconductrice doivent être impérativement retirés afin de garantir des performances optimales. Cette régénération des surfaces est couramment réalisée à l’aide de deux types de polissages chimiques : par BCP (Buffered Chemical Polishing) ou par électro-polissage (EP). Cependant, ces techniques utilisent des acides très concentrés qui entrainent des coûts d’opération très conséquents du fait des problèmes de sécurité. Une voie d’amélioration pouvant rendre possible la construction de telles machines serait de remplacer totalement ou partiellement l’utilisation des acides par des techniques de polissage alternatives.Le polissage mécanique a été étudié durant des décennies et plus spécifiquement les techniques par centrifugation (CBP). Cette technique permet d’atteindre des rugosités de surface bien meilleures et est bien plus efficace pour retirer certains défauts de surface comparé aux procédés chimiques. Cependant, cette technique n’est pas envisageable comme solution alternative à cause des fortes pollutions de surface et des durées de traitement très longues. La première partie de la thèse a consisté à reproduire l’état de l’art, comprendre les limitations réelles de cette technique et essayer d’améliorer le procédé en réduisant la pollution de surface générée par le piégeage des abrasifs en surface ainsi que la durée de traitement (réduction du nombre d’étapes intermédiaires). Il a été conclu que ce procédé ne peut pas être considéré comme alternatif mais complémentaire aux traitements chimiques.La deuxième partie du travail de thèse s’est concentrée sur la méthode de polissage métallographique. Cette dernière ne peut s’appliquer que sur plaques et non sur des géométries complexes, cependant elle retire très efficacement toutes les impuretés et dommages cristallins formés durant la fabrication des tôles de Niobium. Un procédé optimisé à 2 étapes, inspiré des techniques conventionnelles (typiquement 5-6 étapes) a été développé avec succès et optimisé pour les contraintes particulières du Niobium pour les applications SRF. Ce procédé permet non seulement d’obtenir une rugosité de surface incomparable mais préserve également la structure cristalline. Des études complémentaires sont encore requises afin d’améliorer les techniques de formage des tôles ou même caractériser des solutions alternatives permettant des limiter les dégâts en surface et de préserver la qualité du matériau.Finalement, ce travail mené est d’une importance capitale pour le futur des cavités accélératrices supraconductrices, c’est-à-dire l’utilisation de nouveaux matériaux supraconducteurs sous forme de couche mince. La qualité des couches minces de ces matériaux alternatifs dépend très fortement de l’état de surface du substrat (typiquement niobium ou cuivre poly cristallin). / Large-scale production of superconducting radio-frequency (SRF) cavities is an industrial challenge, not only because of the increasing number of unit for future projects but also because of requirements in term of reliability, reproducibility and performances very close to the physical limit of polycrystalline bulk Niobium. Nowadays, XFEL (DESY) and LHC (CERN) are the largest existing accelerators which are based on SRF technology. Even more challenging SRF accelerator projects like ILC (International Linear Collider) and FCC (Future Circular Collider) are being studied. For such large-scale facilities, higher performances, reduction in fabrication and operation costs are required and essential to proceed with industrialization.A pathway to reduce these costs and improve performances has been studied in this work. It consists in optimizing the cleaning process of cavity surfaces. Indeed, pollution and crystal defects on the surface created during fabrication steps of a SRF cavity have to be removed to ensure optimal superconducting performances. In order to get rid of impurities and to recover crystal structure, two polishing techniques are routinely used: the buffered chemical polishing (BCP) and electro-polishing (EP). However, these techniques involve highly concentrated acids, which lead to high operation costs and safety concerns. A way to overcome the aforementioned drawbacks and make the construction of future accelerators possible would be to replace or complement the conventional chemical polishing by alternative polishing techniques.Mechanical polishing has already been applied in SRF-community for decades by using centrifugal barrel polishing (CBP). This technique could provide a better surface roughness and could be more efficient at removing some surface defects compared to EP and BCP. However, this process does not satisfy requirements for large-scale production due to strong surface pollution and an extremely long processing time. The first part of the PhD work consisted in reproducing the state of the art, understanding its limitations and optimizing the recipe by the reduction of the surface pollution (embedded abrasives) and processing time (reduction of intermediate steps). As a conclusion to this first study, CBP could only be a complementary polishing technique to chemical treatments.The second part of the work focused on metallographic flat polishing. This technique cannot be directly applied on enclosed geometries however, it can remove efficiently surface defects (impurities and crystal damages) created during the fabrication of Niobium sheet. A 2-step process, inspired from metallographic techniques (typically 5-6 steps) has been successfully developed and optimized on Niobium for SRF applications. This process provides not only an improved roughness compared to conventional chemical treatments but also preserve the crystal quality underneath the surface, over the field penetration depth. Additional studies have to be now carried out to optimize conventional forming process or characterize alternative techniques to limit surface damages and preserve material quality as much as possible.Last but not least, the work done is of first importance for the future of SRF cavities meaning the use of new superconducting materials as thin films. The quality of thin-films of alternative superconductors depends strongly on the surface state of the substrate, typically polycrystalline bulk Niobium or Copper.

Alkali-Aggregate Reaction (AAR) is one of the most harmful distress mechanisms affecting the serviceability and durability of concrete critical infrastructure worldwide. Over the past decades, several approaches and recommendations have been developed to assess the potential reactivity of aggregates in the laboratory and the efficiency of preventive measures (e.g., supplementary cementing materials – SCMs) to mitigate ASR in the field. Yet, recent findings suggest that the appropriate use of SCMs “only” delayed and does not entirely prevent ASR occurrence. Moreover, once ASR starts in the field, there is no “universal” solution that should be applied in various cases, and each situation should be evaluated as “unique”. Nevertheless, artificially triggering healing agents have been studied in the late years, thus presenting an interesting “physical” solution to reduce the ingress of water and recover damaged concrete elements, which could present an interesting solution for durability-related distress due to ASR. This Ph.D. project focuses on detailed laboratory investigations aiming first to understand the self-healing process of concrete (i.e., by the natural or engineered process). Then, its further influence on ASR-induced expansion and deterioration, either applied internally or externally to the concrete. To achieve this goal, concrete mixtures presenting a wide range of binder compositions, using distinct types of chemical admixtures (e.g., crystalline self-healing), and incorporating five different types/nature of highly reactive aggregates (i.e., coarse and fine) were combined to manufactured concrete specimens in the laboratory. Otherwise, in aging specimens, concrete samples were designed only with GU-cement as the binder material but incorporated two different types/nature of highly reactive aggregates. Then, the samples were exposed to ASR-induced development until they reached pre-determined expansion levels, in which a wide range of sealers and coating materials were applied on the surface of the affected specimens. Mechanical (i.e., stiffness damage test, modulus of elasticity, micro indentation, shear and compressive strengths) and microscopic (damage rating index and scanning electron microscopy) tests were performed on samples at different ages (up to two years of accelerated ASR development). The results show that besides changing AAR-kinetics, the different binder compositions or the chemical admixtures could modify the distress mechanism due to AAR. The addition of crystalline healing agents or their combination with SCMs in concrete not only delayed the development of inner damage but significantly lowered the compressive strength loss at equivalent expansion amplitudes than control specimens. Moreover, the combination of different binder materials modified the chemical and mechanical properties of the ASR-gel, changing its swelling properties and the further damage development in concrete. On the other hand, the wide range of surface treatments used were not able to alter ASR distress mechanism; yet, they changed ASR-kinetics. Moreover, their effectiveness to slower the reaction shows to be significantly influenced by the damage degree to which the surface treatment is applied. Finally, a comprehensive framework enabling the optimized selection of raw materials to prevent or mitigate ASR development is proposed.

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This is a case study made in collaboration with Proton Finishing AB to investigate the usage of Automated Guided Vehicles (AGV) in a surface treatment company. AGVs is a self-driving unit used for material transport in workplaces and logistics settings. In this study, the following research questions have been explored: ● What are the benefits of using AGVs trucks in a surface treatment company? ● What are the disadvantages of using AGVs in a surface treatment company? ● How can 5G impact the use of AGVs in the warehouse of a surface treatment company compared to AGVs with a traditional solution? ● Which model of AGV meets the requirements for warehouse management at Proton Finishing AB compared to other models? The theory was collected from relevant literature collected by the researchers at the library of Linnéuniversitetet and papers on scientific research. The empirical material was collected through semi-structured interviews with different suppliers of AGVs, a Cyber Security consultant, a Project Manager specialized in Private Networks and employees from Proton Finishing AB. There were several findings discovered with AGVs in a surface treatment company. Benefits and disadvantages were identified. The researchers discovered what model of AGV was most suitable for Proton Finishing AB’s warehouse. With help from the collected theory and empirical data, the researchers were able to suggest the most suitable AGV and propose how the implementation of AGVs can be done with 5G.

The purpose of this research was to identify the types of surface treatments available for use on concrete bridge decks and to determine which materials are most capable of providing long-term protection from contamination by chloride ions. The products addressed in this report primarily include urethanes, silicon-based sealers, and epoxies. An extensive literature review was conducted to document common overlay distresses, performance histories, and properties of specific surface treatment products currently available in the industry. In addition, three reports summarizing in-house experiments performed by the Utah Department of Transportation between 1995 and 2003 regarding various types of surface treatments were reviewed as part of this research. Finally, a nationwide questionnaire survey was conducted to investigate the state-of-the-practice with regard to surface treatment applications on bridge decks by state departments of transportation throughout the United States. Of the three types of materials addressed in this research, epoxy-based products have the greatest ability to protect concrete and remain uncracked with an acceptable level of skid resistance. Silicon-based products do not crack because they seep into the pores of the concrete, but they do not protect the concrete from the wearing effects of traffic or improve skid resistance. Published field studies indicate that urethane surface treatments do not resist the effects of traffic as well as epoxy-based materials, nor do they offer a substantial decrease in expense or health risk when compared to epoxy-based products. The results of the nationwide questionnaire clearly indicate that bridge deck surface treatments are valuable as both chloride barriers and skid-resistant wearing courses. No standard practice appears to exist with regard to timing of surface treatments, however. Some states arbitrarily apply surface treatments at 10 to 12 years after construction, other states wait until cracking has become fairly considerable before action is taken, and still other states apply surface treatments when the chloride content of the concrete reaches a certain level. Because concrete decks with significant cracking are not ideal substrates for polymer applications, surface treatments should be applied as preventive measures early in the service lives of bridge decks to effectively prevent chloride concentrations from reaching critical levels. This research suggests that epoxy-based surface treatments should be specified for concrete bridge decks when both a chloride barrier and improved skid resistance are desired. If a chloride barrier is all that is needed or desired, a silane surface treatment should be considered; silane treatments are less expensive and easier to apply than epoxy treatments. When a large amount of epoxy is to be mixed, automatic proportioning equipment that can precisely monitor and control the ratios of components should be employed.

Bridge engineers and managers in coastal areas and cold regions frequently specify the application of surface treatments on concrete bridge decks as barriers against chloride ingress. In consideration of concrete cover thickness and the presence of stay-in-place metal forms (SIPMFs), the objective of this research was to determine the latest timing of initial surface treatment applications on concrete bridge decks subjected to external chloride loading before chlorides accumulate in sufficient quantities to initiate corrosion during the service life of the deck. Chloride concentration data for this research were collected from 12 concrete bridge decks located within the I-215 corridor in Salt Lake City, Utah. Numerical modeling was utilized to generate a chloride loading function and to determine the diffusion coefficient of each deck. Based on average diffusion coefficients for decks with and without SIPMFs, chloride concentration profiles were computed through time for cover thicknesses of 2.0 in., 2.5 in., and 3.0 in. The results of the work show that the average diffusion coefficient for bridge decks with SIPMFs is approximately twice that of decks without SIPMFs and that, on average, each additional 0.5 in. of cover beyond 2.0 in. allows an extra 2 years for decks with SIPMFs and 5 years for decks without SIPMFs before a surface treatment must be placed to prevent excessive accumulation of chlorides. Although the data generated in this research are based on conditions typical of bridge decks in Utah, they clearly illustrate the effect of cover depth and the presence of SIPMFs. Given these research findings, engineers should carefully determine the appropriate timing for initial applications of surface treatments to concrete bridge decks in consideration of cover depth and the presence of SIPMFs. For maintenance of concrete bridge decks with properties similar to those tested in this study, engineers should follow the guidelines developed in this research to minimize the ingress of chlorides into the decks over time and therefore retard the onset of reinforcement corrosion; altogether separate guidelines may be needed for decks having substantially different properties. Surface treatments should be replaced as needed to ensure continuing protection of the concrete bridge deck against chloride ingress.