Innovative Fertigung von Leiterplatten durch FDM-Druck und selektive Kunststoffmetallisierung. - In: WOMag, ISSN 2195-5891, Bd. 12 (2023), 4, S. 9-11
Mit Hilfe von additiven Fertigungsverfahren lassen sich Kunststoffe mit unterschiedlichen Eigenschaften zu einem Produkt kombinieren. Dies erlaubt es, die Grundeinheiten von elektrischen Leiterplatten mittels Drucktechnik herzustellen, wobei der Aufwand weitgehend unabhängig von der hergestellten Stückzahl ist. Durch Drucken mit metallisierbaren Kunststoffen gelingt es, Leiterbahnen mit akzeptabler Leitfähigkeit auf elektrisch isolierendem Trägermaterial zu erzeugen. Die bisherigen Entwicklungen sind auf die Verwendung von Kunststoff mit einer maximalen Temperaturbelastung bis etwa 100 ˚C beschränkt. Um die bestehenden Verfahren der Leiterplattentechnik nutzen zu können, muss diese Temperaturobergrenze deutlich erhöht werden.
Electrochemical deposition of silicon in organic electrolytes. - In: Reference module in chemistry, molecular sciences and chemical engineering, (2023)
Electrodeposition is a versatile instrumental technique, already applied in many industrial fields. However, the deposition of silicon and other reactive elements is still challenging and requires further research and improvement. Accomplishing an efficient electrodeposition of silicon at room temperature is very attractive due to the high number of manufacturing technologies that would benefit from this approach. This work provides an overview of the electrochemical approaches for silicon deposition performed in organic electrolytes. The main factors that impact this process are individually discussed and exemplified with appropriately updated literature sources. Furthermore, the previously available research on characterization of electrodeposited silicon containing layers is provided. These studies are presented in the context of better understanding the structure, composition, and functional properties of the deposited silicon material, which may attract the attention of young academic scientists and process engineers.
https://doi.org/10.1016/B978-0-323-85669-0.00005-2
Monitoring considerations of second life lithium ion batteries in battery energy storage systems. - In: PCIM Europe 2022, (2022), S. 1905-1914
This paper presents an analytical study of the most important technical aspects that should be considered in the methodologies for monitoring second-life lithium-ion batteries in stationary energy storage systems. The study is based, on one hand, on the specificity of these batteries in terms of changing their response differently in the second-life than in the first to external and operational influences. On the other hand, it is based on the monitoring requirements of storage systems to obtain an improved monitoring system with sufficient accuracy and more efficient performance of batteries in their second-life.
https://doi.org/10.30420/565822263
Incorporating state of charge estimation methods towards more accurate monitoring of second-life lithium-ion batteries. - In: 2022 13th International Renewable Energy Congress (IREC), (2022), insges. 6 S.
Although several methods are developed for estimating the state of charge of lithium-ion batteries, there is still a challenge regarding monitoring the second life of these batteries due to the expected difference in the behavior and operating conditions in their second life. Considering that each method has its advantages and disadvantages according to the application and operating conditions, and monitoring the batteries in their second life is of special importance because it is required to integrate with the battery management system to balance cells, diagnose faults and prevent overheating. Therefore, the estimation method developed in this study, by incorporating artificial neural network method and Kalman filter method with fine-tuning of the filtering process using Coulomb counting, provides a solution for more accurate online monitoring of these batteries. Aiming to get the best possible performance, considering the specificity of the second life of the batteries in terms of operating voltage, low values of expected capacity, discharge ratio and other operational parameters.
https://doi.org/10.1109/IREC56325.2022.10002052
Innovation processing of circuit boards with FDM printing and selective electrochemical metallization. - In: Meeting abstracts, ISSN 2151-2043, Bd. MA2022-01 (2022), 57, 2369
https://doi.org/10.1149/MA2022-01572369mtgabs
A systematic approach for controlling electrodeposition based on studies of an acidic copper electrolyte. - Ilmenau : Universitätsbibliothek, 2022. - 1 Online-Ressource (122 Seiten)
Technische Universität Ilmenau, Dissertation 2022
Bekannte akademische Erkenntnisse der Elektrochemie, wie die Butler-Volmer Kinetik, und deren Veränderungen ermöglichen unter anderem einen genaueren Einblick in den Mechanismus der Metallabscheidung. Aufgrund eines fehlenden Bindegliedes wurden diesen akademischen Erkenntnissen keine oder nur wenig Beachtung in der industriellen Prozessüberwachung geschenkt. Stattdessen wird die Hull-Zell-Abscheidung als indirekter Ansatz für die Analyse des Abscheidungsverhaltens benutzt. Durch die Entwicklung einer Methode, die die Randelemente-Methode als Grundlage für die Simulation verwendet, werden die kinetischen Parameter - die Austauschstromdichte j0 und der Transferkoeffizient α - aus experimentellen Hull-Zellen-Abscheidungen gewonnen (Rückwärtsbestimmung). Dieser Ansatz wird validiert, indem zyklische voltammetrische Daten eines sauren Kupferelektrolyten in die Simulation eingesetzt und die simulierten Hull-Zellkurven mit experimentellen Kurven verglichen werden. Darüber hinaus wird der Einfluss von Additiven auf das kinetische Verhalten untersucht, ohne die visuellen Informationen und die Möglichkeiten zu verlieren, die strukturellen und physikalischen Eigenschaften der Metallabscheidung zu erhalten. Dieser Ansatz kann zu einem tieferen elektrochemischen Verständnis von industriell benutzten Elektrolyten führen.
https://doi.org/10.22032/dbt.55223
Abscheidung von Aluminiumlegierungen aus ionischen Flüssigkeiten. - In: Galvanotechnik, ISSN 0016-4232, Bd. 113 (2022), 10, S. 1299-1304
Umweltfreundliche Schichten aus Aluminiumlegierungen werden gegenüber Schichten aus bedenklichen Metallen wie Cadmium zunehmend interessanter. Allerdings können sie mittels galvanischer Verfahren nur aus aprotischen Elektrolyten, wie ionischen Flüssigkeiten, abgeschieden werden. Um eine hohe Prozessstabilität zu erzielen, können Multianoden eingesetzt werden.
Characterization of a magnesium fluoride conversion coating on Mg-2Y-1Mn-1Zn screws for biomedical applications. - In: Materials, ISSN 1996-1944, Bd. 15 (2022), 22, 8245, S. 1-18
MgF2-coated screws made of a Mg-2Y-1Mn-1Zn alloy, called NOVAMag® fixation screws (biotrics bioimplants AG), were tested in vitro for potential applications as biodegradable implants, and showed a controlled corrosion rate compared to non-coated screws. While previous studies regarding coated Mg-alloys have been carried out on flat sample surfaces, the present work focused on functional materials and final biomedical products. The substrates under study had a complex 3D geometry and a nearly cylindrical-shaped shaft. The corrosion rate of the samples was investigated using an electrochemical setup, especially adjusted to evaluate these types of samples, and thus, helped to improve an already patented coating process. A MgF2/MgO coating in the µm-range was characterized for the first time using complementary techniques. The coated screws revealed a smoother surface than the non-coated ones. Although the cross-section analysis revealed some fissures in the coating structure, the electrochemical studies using Hanks’ salt solution demonstrated the effective role of MgF2 in retarding the alloy degradation during the initial stages of corrosion up to 24 h. The values of polarization resistance (Rp) of the coated samples extrapolated from the Nyquist plots were significantly higher than those of the non-coated samples, and impedance increased significantly over time. After 1200 s exposure, the Rp values were 1323 ± 144 Ω.cm2 for the coated samples and 1036 ± 198 Ω.cm2 for the non-coated samples, thus confirming a significant decrease in the degradation rate due to the MgF2 layer. The corrosion rates varied from 0.49 mm/y, at the beginning of the experiment, to 0.26 mm/y after 1200 s, and decreased further to 0.01 mm/y after 24 h. These results demonstrated the effectiveness of the applied MgF2 film in slowing down the corrosion of the bulk material, allowing the magnesium-alloy screws to be competitive as dental and orthopedic solutions for the biodegradable implants market.
https://doi.org/10.3390/ma15228245
Hollow platinum-gold and palladium-gold nanoparticles: synthesis and characterization of composition-structure relationship. - In: Journal of nanoparticle research, ISSN 1572-896X, Bd. 24 (2022), 12, 245, insges. 15 S.
Hollow palladium-gold (PdAu) and platinum-gold (PtAu) alloy nanoparticles (NPs) were synthesized through galvanic replacement reactions. PdAu NPs denoted PdAu-99.99 and PdAu-98 were produced using palladium precursors with different purity degree: Na2PdCl4 ≥ 99.99% and Na2PdCl4 98%, respectively. The effect of the addition time of the gold palladium precursor solution on the size of the generated NPs was evaluated. Two types of particles, with a rough and a smooth surface, were identified in the suspensions of PtAu and PdAu NPs by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The atomic percentage of gold, platinum, palladium, and cobalt (atomic %) in the nanoparticles was determined by energy dispersive X-ray spectroscopy (EDX). PtAu NPs (26-42 nm) contain Pt (41 at%), Au (36 at%), and Co (23 at%). Two groups of hollow palladium gold NPs (30-50 nm) with a different residual cobalt content were produced. PdAu-99.99 NPs consisted of Pd (68 at%), Au (26 at%), and Co (6 at%), whereas PdAu-98 NPs were composed of Pd (70 at%), Au (22 at%), and Co (8 at%). The hollow structure of the NPs was confirmed by EDX line scanning. Selected area electron diffraction analysis (SAED) revealed the formation of PtAu and PdAu alloys and it was used in estimating the lattice parameters, too.
https://doi.org/10.1007/s11051-022-05619-9
Tribological and mechanical performance of Ti2AlC and Ti3AlC2 thin films. - In: Advanced engineering materials, ISSN 1527-2648, Bd. 24 (2022), 10, 2200188, S. 1-11
Mn+1AXn (MAX) phases are novel structural and functional materials with a layered crystal structure. Their unique properties such as good machinability, high electrical conductivity, low friction, and corrosion resistance are appealing for many engineering applications. Herein, Ti2AlC and Ti3AlC2 MAX thin films are synthesized by magnetron sputtering and subsequent thermal annealing. A multilayer approach is used to deposit single-element nanolayers of titanium, aluminum, and carbon onto silicon substrates with a double-layer-diffusion barrier of SiO2 and SixNy. Ti2AlC and Ti3AlC2 thin films (thickness ≈500 nm) are formed via rapid thermal annealing and verified by X-Ray diffraction. Nanoindentation tests show hardness values of about 11.6 and 5.3 GPa for Ti2AlC and Ti3AlC2, respectively. The tribological behavior of the Ti2AlC and Ti3AlC2 thin films against AISI 52100 steel balls under dry sliding conditions is studied using ball-on-flat tribometry. The resulting coefficient of friction (CoF) for Ti2AlC and Ti3AlC2 ranges between 0.21-0.42 and 0.64-0.91, respectively. The better tribological behavior observed for Ti2AlC thin films is ascribed to its smaller grain size, reduced surface roughness, and higher hardness.
https://doi.org/10.1002/adem.202200188