László Péter, Imre BakonyiE, Vandri Ahmad Isnaini#, Lajos PogányA, Sándor Zsurzsa#
Component distribution of electrodeposited alloys. — Electrodeposited alloys prepared with constant current density exhibit a unique near-substrate component distribution. The preferentially deposited metals accumulate near the substrate, and the decay of the initial zone of uneven composition is 150-200 nm thick regardless of the alloy constituents. This effect has a great importance in the deposition of nanostructures in which the total layer thickness is often less than the decay length scale of the spontaneous composition variation.
It was shown that two countermeasures can provide deposits with even composition also in the near-substrate zone: a, application of pulse plating, and b, the application of uniform convection conditions. The results related to many deposit compositions were summarized in a comprehensive review article.
Special attention was devoted to the composition depth profile of Fe-Co-Ni deposits. It was shown that the composition variation as measured with either sputtering-based depth profiling methods or cross-sectional scans in a transmission electron microscope (TEM) are essentially identical. The advantage of the application of the TEM was that the length scale of the composition variation and that of the change in the crystallographic properties (grain size and orientation) could be seen for identical samples. It was revealed that variations in the composition and in the crystallographic properties are independent of each other. (This work was performed in co-operation with the Josef Stefan Institute, Ljubljana, Slovenia.)
Structural properties of electrodeposited metals. — The structural properties of electrodeposited nanocrystalline Ni films were analyzed with TEM and X-ray line profile analysis (XLPA). The effect of saccharin as organic additive on the microstructure, texture and hardness was studied. The addition of the saccharin to the plating baths eliminated the texture and yielded very fine microstructures with high dislocation densities and twin fault probabilities for all solution types tested. A strong correlation was found between the defect density and the grain size.
A plating bath based on nickel sulfate and sodium citrate was developed for the deposition of crack-free Ni–Mo alloy layers of d > 20 m thickness with varying Mo content up to 6 mol%.
The increase in the Mo content resulted in a larger dislocation density and twin fault probability as well as a smaller grain size. The presence of saccharin as additive in the bath and the incorporated sulfur content due to the saccharin decomposition led to a further decrease in the grain size. The Mo content of the alloy improved the thermal stability of the alloys, while the sulfur incorporation had an adverse effect. The sulfur-free Ni94Mo6 alloy
E Professor Emeritus
# Ph.D student
A Associate fellow
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conserved its nanocrystalline nature with < 50 nm grain size up to 800 K, even though the twin faults and the dislocations annihilate under this annealing condition.
(All works related to the structural studies were performed in co-operation with the Eötvös University and the Centre for Energy Research of the Hungarian Academy of Sciences.) Industry-oriented research activities. — Electrodeposition has long been playing a vital role in surface finishing by being able to produce a variety of metallic coatings on product surfaces for protective, decorative and various other functional purposes. At a certain level of technological development, there was an increasing demand for coatings with improved deposit performance. This need was the driving force behind the elaboration of new electrodeposition methods, which enable the preparation of coatings with their composition varying along the thickness. Such “compositionally graded coatings” can be classified as compositionally modulated alloys (CMA) or multilayers. In the case of a CMA coating, the alloy deposit composition is continuously modulated along the thickness. In the case of a multilayer coating, the deposit consists of an alternating sequence of two layers with different chemical compositions whereby the constituent individual layers can have a thickness even down to the nanometer scale (for metallic materials, 1 nm corresponds to roughly 4-5 monatomic layers). In collaboration with the Hirtenberger Engineered Surfaces (HES), Austria, we have provided an overview of the development of various pulse-plating methods for the preparation of compositionally graded coatings from a single bath. As a particular case, the historical development of corrosion-protective electrodeposited multilayers based on the Zn-Fe system and their state of the art was exemplified. This overview was presented at the last European Pulse Plating Seminar in Vienna, organized biannually by HES and was published as a review paper in one of the leading journal of industrial surface finishing.
Calculations taking into account various chemical equilibra (acid-base, complex formation and partition between phases) were performed in order to establish a technique combining dual-phase potentiometric lipophilicity measurement with the partition coefficient method. With a negligible simplification, a linear equation was obtained for calculating both the acid dissociation and the complex formation constants. The method developed proved to be suitable for testing the lipophilicity of drug candidates by using smaller quantities and much less expensive instrumentation than conventional techniques. The complex-formation constants obtained for all drug candidate compounds tested reproduced very well the values reported by using other methods. (This work was performed in co-operation with the following partners: Compound Profiling Laboratory of the Gedeon Richter Plc., Budapest University of Technology and Economics and Cyclolab Cyclodextrin Research and Development Ltd.)
Grant
Research Cooperation Project “Periodic magnetic nanostructures by electrochemical approaches: a novel route towards the fabrication of magnonic crystals” supported by the Humboldt Foundation Research Group Linkage Programme between the Wigner RCP and the Leibniz Institute IFW-Dresden (Hungarian project leader: I. Bakonyi, 2017-2019)
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International cooperation
COST Action MP1407 (17 COST and 3 non-COST countries): Electrochemical processing methodologies and corrosion protection for device and systems miniaturization: e-MINDS (Management Committee members: I. Bakonyi and L. Péter, 2015-2019)
MTA NKM-8/2018 (Hungarian-Bulgarian bilateral academic exchange project): Magnetic alloys and multilayers prepared by oscillating electrochemical reactions (Hungarian project leader: L. Péter, 2016-2018)
Publications
Articles
1. Bakonyi I: Guidelines for the evaluation of magnetotransport parameters from measurements on thin strip-shaped samples of bulk metallic ferromagnets with finite residual resistivity. EUR PHYS J PLUS 133:12 521/1-11 (2018)
2. Dargó G, Boros K, Péter L, Malanga M, Sohajda T, Szente L, Balogh GT: Novel medium-throughput technique for investigating drug-cyclodextrin complexation by pH-metric titration using the partition coefficient method. INT J PHARMACEUT 542:1-2 100-107 (2018)
3. Kapoor G, Péter L, Fekete É, Lábár JL, Gubicza J: The influence of Mo addition on the microstructure and its thermal stability for electrodeposited Ni films. MATER CHARACT 145: 563-572 (2018)
4. Kolonits T, Jenei P, Péter L, Bakonyi I, Czigány Zs, Gubicza J: Effect of bath additives on the microstructure, lattice defect density and hardness of electrodeposited nanocrystalline Ni films. SURF COAT TECH 349: 611-621 (2018)
5. Péter L, Rozman KZ, Sturm S: Structure and composition of electrodeposited Fe-Co-Ni alloys studied by transmission electron microscopy. J ELECTROCHEM SOC 165:9 D384-D392/1-9 (2018)
6. Péter L, Vad K, Csik A, Muñíz R, Lobo L, Pereiro R, Šturm S, Žužek Rožman K, Molnár Gy, Németh K, Neuróhr K, Boros K, Pogány L, Bakonyi I: In-depth component distribution in electrodeposited alloys and multilayers. J ELECTROCHEM SCI ENG 8:1 49-71 (2018)
7. Prataap RKV, Arunachalam R, Pavul Raj R, Mohan S, Péter L: Effect of electrodeposition modes on ruthenium oxide electrodes for supercapacitors. CURR APPL PHYS 18:10 1143-1148 (2018)
8. Zsurzsa S, Pellicer E, Sort J, Péter L, Bakonyi I: Electron microscopy characterization of electrodeposited homogeneous and multilayered nanowires in the Ni-Co-Cu system.
J ELECTROCHEM SOC 165:11 D536-D542 (2018) Conference proceedings
9. Kapoor G, Péter L, Fekete É, Gubicza J: Defect structure in electrodeposited nanocrystalline Ni layers with different Mo concentrations. In: Proc. 2nd International Conference on Condensed Matter and Applied Physics (ICC 2017), Bikaner, India, 24-25 November 2017, AIP CONFERENCE PROCEEDINGS 1953:1 030047/1-4 (2018) 10. Trampus P, Dobránszky J, Kerner Z, Knisz J, Oszvald F, Palotás B, Péter L, Réger M, Verő
B.: Comprehensive analysis of local corrosion degradation on austenitic pipeline. In:
Proc. 11th Hungarian Conference on Materials Science, Balatonkenese, Hungary, 15–
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17 October 2017, IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING 426:1 012050/1-9 (2018)
Others
11. Bakonyi I, Péter L: Report on former EU project success: trainee of Marie-Curie-course by EAST became COST action chair. T I MET FINISH 96:4 172-173 (2018)
12. Bakonyi I, Hansal W: Development of pulse-plating technology for the preparation of coatings with varying composition along their thickness: a historical overview. T I MET FINISH 96:5 237-243 (2018)
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