You have 0 saved results.
Mark results and click the "Add To Watchlist" link in order to add them to this list.

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Online Resource  (17)
  • MDPI AG  (17)
  • 1
    In: Entropy, MDPI AG, Vol. 20, No. 7 ( 2018-07-02), p. 505-
    Type of Medium: Online Resource
    ISSN: 1099-4300
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2014734-X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Online Resource
    Online Resource
    MDPI AG ; 2017
    In:  Coatings Vol. 7, No. 9 ( 2017-09-12), p. 144-
    In: Coatings, MDPI AG, Vol. 7, No. 9 ( 2017-09-12), p. 144-
    Abstract: The investigation of high-entropy alloys (HEAs) has revealed many promising properties. HEAs with a high share of Al and Ti are suitable for the formation of lightweight materials. Investigations of the alloy system AlCoCrFeNiTi showed high strength, hardness, ductility, and wear resistance, which makes this special alloy interesting for surface engineering and particularly for thermal spray technology. In this study, the suitability of inert gas-atomised HEA powder for high-velocity-oxygen-fuel (HVOF) thermal spray is investigated. This process allows for high particle velocities and comparatively low process temperatures, resulting in dense coatings with a low oxidation. The microstructure and phase composition of the atomised powder and the HVOF coating were investigated, as well as the wear behaviour under various conditions. A multiphase microstructure was revealed for the powder and coating, whereas a chemically ordered bcc phase occurred as the main phase. The thermal spray process resulted in a slightly changed lattice parameter of the main phase and an additional phase. In comparison with a hard chrome-plated sample, an increase in wear resistance was achieved. Furthermore, no brittle behaviour occurred under abrasive load in the scratch test. The investigation of wear tracks showed only minor cracking and spallation under maximum load.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    Language: English
    Publisher: MDPI AG
    Publication Date: 2017
    detail.hit.zdb_id: 2662314-6
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    In: Metals, MDPI AG, Vol. 7, No. 5 ( 2017-05-09), p. 162-
    Abstract: Alloying aluminum offers the possibility of creating low-density high-entropy alloys (HEAs). Several studies that focus on the system AlCoCrFeNiTi differ in their phase determination. The effect of aluminum on the phase composition and microstructure of the compositionally complex alloy (CCA) system AlxCoCrFeNiTi was studied with variation in aluminum content (molar ratios x = 0.2, 0.8, and 1.5). The chemical composition and elemental segregation was measured for the different domains in the microstructure. The crystal structure was determined using X-ray diffraction (XRD) analysis. To identify the spatial distribution of the phases found with XRD, phase mapping with associated orientation distribution was performed using electron backscatter diffraction. This made it possible to correlate the chemical and structural conditions of the phases. The phase formation strongly depends on the aluminum content. Two different body-centered cubic (bcc) phases were found. Texture analysis proved the presence of a face-centered cubic (fcc) phase for all aluminum amounts. The hard η-(Ni, Co)3Ti phase in the x = 0.2 alloy was detected via metallographic investigation and confirmed via electron backscatter diffraction. Additionally, a centered cluster (cc) with the A12 structure type was detected in the x = 0.2 and 0.8 alloys. The correlation of structural and chemical properties as well as microstructure formation contribute to a better understanding of the alloying effects concerning the aluminum content in CCAs. Especially in the context of current developments in lightweight high-entropy alloys (HEAs), the presented results provide an approach to the development of new alloy systems.
    Type of Medium: Online Resource
    ISSN: 2075-4701
    Language: English
    Publisher: MDPI AG
    Publication Date: 2017
    detail.hit.zdb_id: 2662252-X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    In: Coatings, MDPI AG, Vol. 12, No. 8 ( 2022-08-17), p. 1205-
    Abstract: The influence of chemical redissolution in the PEO layer-growth equilibrium on aluminum is evaluated differently in literature. In order to estimate whether and to what extent various alumina modifications could be affected by redissolution processes during PEO, immersion experiments were carried out on PEO coatings in model electrolytes of different alkalinity and silicate concentration. Their composition was determined spectroscopically before and after the experiments. The layers were characterized by XRD before and after the tests and examined at affected and unaffected zones using SEM, EDX, and EBSD. The results show that chemical oxide dissolution can only be observed at the layer/substrate interface and that primarily amorphous alumina is affected. This process is intensified by higher alkalinity and inhibited by silicate additives. The crystalline Al2O3 modifications show no significant attack by the electrolytes used. Transferring these observations to plasma electrolytic oxidation, they allow the conclusion that the electrochemically active zone in the pore ground of discharge channels interacts with the electrolytic and electrical process parameters throughout the entire PEO procedure. Influences of bath alkalinity and silicate content on layer growth rates are to be understood as impact on the passivation processes at the layer/substrate interface rather than chemical redissolution.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662314-6
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    In: Coatings, MDPI AG, Vol. 10, No. 6 ( 2020-06-09), p. 553-
    Abstract: Ag–W two-phase system was prepared by electrodeposition using anhydrous 1-ethyl-3-methylimidazolium chloride [EMIm]Cl ionic-liquid (IL) solution with AlCl3 in different ratios. The deposition took place outside the glove box with a continuous Ar stream over the electrolyte at 120 °C and a pulsed-like current regime. Resultant layers show areas of Ag and W with an overall W content with a mass fraction of w W   = 50% (mole fraction x W   = 36.9%). The phase composition of Ag–W layers was observed by X-ray diffraction, and the chemical composition was characterized by scanning electron microscopy and inductively coupled plasma optical emission spectroscopy.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2662314-6
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    In: Coatings, MDPI AG, Vol. 13, No. 3 ( 2023-03-20), p. 656-
    Abstract: Potentiodynamic and potentiostatic polarization tests in the potential range between open circuit potential (OCP) − 0.1 V and OCP + 4 V were carried out in aluminate–phosphate electrolytes with an aluminate concentration of 0.2 mol/L and varying phosphates contents between 0 and 0.1 mol/L. The pH was adjusted between 11.5 and 12.0 due to phosphate and optional KOH addition. A high-strength, dual-phase steel, which is relevant for lightweight construction, served as the substrate material. The layer microstructure was investigated by optical and scanning electron microscopy. Energy-dispersive X-ray spectroscopy and Raman spectroscopy were used for element and phase analyses. We found that iron hydroxides or oxides are initially formed independently of the electrolyte composition at low potentials. At around 1 V vs. standard hydrogen electrode (SHE), the current density suddenly increases as a result of oxygen evolution, which causes a significant reduction in the pH value. Precipitation leads to the formation of porous layers with thicknesses of 10 µm to 20 µm. In the case of a pure aluminate solution, the layer mainly consists of amorphous alumina. When adding phosphate to the electrolyte, the layer additionally contains the hydrous phosphate evansite. At the highest phosphate content in the electrolyte, the highest P content and the most pronounced crack network were observed.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662314-6
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    In: Algorithms, MDPI AG, Vol. 14, No. 4 ( 2021-03-30), p. 113-
    Abstract: Three-component systems of diffusion–reaction equations play a central role in the modelling and simulation of chemical processes in engineering, electro-chemistry, physical chemistry, biology, population dynamics, etc. A major question in the simulation of three-component systems is how to guarantee non-negative species distributions in the model and how to calculate them effectively. Current numerical methods to enforce non-negative species distributions tend to be cost-intensive in terms of computation time and they are not robust for big rate constants of the considered reaction. In this article, a method, as a combination of homotopy methods, modern augmented Lagrangian methods, and adaptive FEMs is outlined to obtain a robust and efficient method to simulate diffusion–reaction models with non-negative concentrations. Although in this paper the convergence analysis is not described rigorously, multiple numerical examples as well as an application to elctro-deposition from an aqueous Cu2+-(β-alanine) electrolyte are presented.
    Type of Medium: Online Resource
    ISSN: 1999-4893
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2455149-1
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    In: Coatings, MDPI AG, Vol. 11, No. 3 ( 2021-03-09), p. 310-
    Abstract: Thick Cu−Sn alloy layers were produced in an [EMIM]Cl ionic-liquid solution from CuCl2 and SnCl2 in different ratios. All work, including the electrodeposition, took place outside the glovebox with a continuous argon stream over the electrolyte at 95 °C. The layer composition and layer thickness can be adjusted by the variation of the metal-salts content in the electrolyte. A layer with a thickness of up to 15 µm and a copper content of up to ωCu = 0.86 was obtained. The phase composition was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). Furthermore, it was found that the relationship between the alloy composition and the concentration of the ions in the electrolyte is described as an irregular alloy system as according to Brenner. Brenner described such systems only for aqueous electrolytes containing complexing agents such as cyanide. In this work, it was confirmed that irregular alloy depositions also occur in [EMIM] Cl.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662314-6
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    In: Computation, MDPI AG, Vol. 9, No. 5 ( 2021-04-27), p. 55-
    Abstract: Thermodynamic equilibria and concentrations in thermodynamic equilibria are of major importance in chemistry, chemical engineering, physical chemistry, medicine etc. due to a vast spectrum of applications. E.g., concentrations in thermodynamic equilibria play a central role for the estimation of drug delivery, the estimation of produced mass of products of chemical reactions, the estimation of deposited metal during electro plating and many more. Species concentrations in thermodynamic equilibrium are determined by the system of reactions and to the reactions’ associated stability constants. In many applications the stability constants and the system of reactions need to be determined. The usual way to determine the stability constants is to evaluate titration curves. In this context, many numerical methods exist. One major task in this context is that the corresponding inverse problems tend to be unstable, i.e., the output is strongly affected by measurement errors, and can output negative stability constants or negative species concentrations. In this work an alternative model for the species distributions in thermodynamic equilibrium, based on the models used for HySS or Hyperquad, and titration curves is presented, which includes the positivity of species concentrations and stability constants intrinsically. Additionally, in this paper a stabilized numerical methodology is presented to treat the corresponding model guaranteeing the convergence of the algorithm. The numerical scheme is validated with clinical numerical examples and the model is validated with a Citric acid–Nickel electrolyte. This paper finds a stable, convergent and efficient methodology to compute stability constants from potentiometric titration curves.
    Type of Medium: Online Resource
    ISSN: 2079-3197
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2723192-6
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Online Resource
    Online Resource
    MDPI AG ; 2023
    In:  Materials Vol. 16, No. 17 ( 2023-08-31), p. 6000-
    In: Materials, MDPI AG, Vol. 16, No. 17 ( 2023-08-31), p. 6000-
    Abstract: The grain size of a metallic coating or the surface layer after the machining of metallic parts strongly impacts corrosion and wear properties along with fatigue behavior. By measuring the combined electrical resistance of this layer and the substrate using the four-point probe method, the grain size of the layer can be determined. For different grain shapes, models are derived based on an analytical approach. The parameters in the models can be determined by appropriate calibration measurements. As a result, the grain sizes can be determined quickly with a non-destructive method, which can be applied to ensure consistent coating or machining results as part of quality control routines in industrial processes.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2487261-1
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages