Tamás Török | Miskolc University (original) (raw)

Papers by Tamás Török

The publications of the MultiScience - XXXI. MicroCAD International Scientific Conference, 2017

Multidiszciplináris tudományok, 2021

The investigation in this paper is based on the existence of carbon content and its role in the f... more The investigation in this paper is based on the existence of carbon content and its role in the formation of Fe-Al intermetallic layer in unalloyed carbon steel C45 with a carbon content of 0.44 wt.%. Several sophisticated techniques such as PFIB SEM equipped with EDS and EBSD, GD-OES were employed for the in-depth surface analysis. The results of the metallographic examination reveal that the carbon would appear and could be well detected at the interface between the solidified aluminum and the solid iron-base steel substrate and got also incorporated in the top aluminum layer. Furthermore, due to the dissolution and outward diffusion of iron into the liquid aluminum melt during the HDA process, plus its involvement in the formation of the solid intermetallic surface layer, thus the carbon atoms gaining higher chemical affinity there will also be more likely to form carbide precipitates of different kinds like Fe3AlC and AlC inside these developing surface layers on the C45 type st...

Authorea

Abstract This research paper presents an analysis of the corrosion properties of steel-reinforced... more Abstract This research paper presents an analysis of the corrosion properties of steel-reinforced concrete samples during immersion in 3.5 wt. % NaCl aqueous solution by measuring their response both cathodic and anodic polarization in order to determine the corrosion rates in the function of their calcium nitrate inhibitor content. This cheap inorganic inhibitor was added to the concrete mix in concentrations of 1% and 3% by weight of cement in addition to two different superplasticizers (MapeiDynamon SR 31 and Oxydtron). The compressive strengths of the so prepared samples were also checked according to the relevant European standard and were within the acceptable limits, so this inhibitor does not weaken this important property of the concrete samples. The test results on steel reinforced samples immersed in 3.5 wt. % NaCl aqueous solutions at room temperature showed promising corrosion mitigating effects just after 6 months testing period. After 6 months the lower corrosion currents (i.e. better corrosion resistance) for both types of superplasticizers were observed with those samples which contained 3% calcium nitrate inhibitor. The best result was observed with sample C4 (in this case 3% calcium nitrate was added to the mixture of cement+Oxydtron superplasticizer). The advantageous inhibition mechanism of nitrate anions is also discussed and interpreted.

Metallurgical and Materials Transactions A, 2016

There is a rather different art compared to the com m n batch type processes within the domain of... more There is a rather different art compared to the com m n batch type processes within the domain of continuous cathodic deposition of metals on wires. In the case of direct electroplating of copper onto the cylindrical surfa ce of a drawn steel wire running with high speed it is not at all an easy task to control all the deposition parameters satisfactorily in order to ensure good adhesion and all the other pro perties required for further processing. In this respect, the relatively newly introduced coppe r yrophosphate baths brought about also new challenges which were among our primary motivat ions in launching a research project in cooperation with a company in Hungary where copp er and zinc plated steel core wires are produced. While aiming at studying the effects of the major parameters influencing the properties of copper layers formed by cathodic depo sition, several sets of experiments were performed in a laboratory Hull cell under varied ci rcumstances. The thin copper layers...

Magazine of civil engineering, 2020

Adott funkcionalis celra, gyakran csak kulonleges felulettechnikai modszereket alkalmazva lehet o... more Adott funkcionalis celra, gyakran csak kulonleges felulettechnikai modszereket alkalmazva lehet optimalisan osszehangolni a hordozo (szubsztratum) es a bevonat anyagi es műszaki jellemzőit. A projekt kereteben, aluminium (AlMg2) hordozora valasztottunk le negyfele felulet-előkezeles utan nikkel-foszfor (Ni-P) retegeket. A ~8%-os P tartalom mellett mar zomeben amorf szerkezetű Ni-P bevonatok osszetetelet, mikroszerkezetet, porozitasat, korrozioallosagat, szilardsagat, tapadasat es vegső soron ezektől a jellemzőktől fuggő lehetseges alkalmazasi koret lenyegesen befolyasolja az, hogy peldaul csak a gondosan tisztitott passziv vagy tobbe kevesbe aktiv feluletű AlMg2 szubsztratumra, vagy annak cink vagy nikkel filmmel (kontakt redukcios precipitacioval) bevont, azaz modositott feluletere valasztjuk-e le a Ni-P reteget. A jelen munka kereteben egy ujszerű, alternativ felulet-előkezelesi (hipofoszfitos martasos) modszert is kifejlesztettunk, mellyel kevesebb műveleti lepesben es az előzőek...

Tin electroplated copper sheets were analysed, with the aim of characterizing the structure of th... more Tin electroplated copper sheets were analysed, with the aim of characterizing the structure of the thin film layer deposited on the substrate. The sel ected raw materials and the plating process are commonly used in the electronics industry for the m anufacturing of printed circuit boards. In addition , we used a Hull cell to show the effects of current density distribution on layer deposition. Our research study involved SEM, GD-OES, and optical stereomicroscopic examinations, employed for the structural and qualitative evaluation of layer properties (“layer goodness”). It is clearly visibl e from the results, that bath composition is not indi fferent in the electroplating process: i.e. the distinctive compounds of the bath will be detectabl e in the outer layers of the coating. Though at hig h current densities, the coating became spongy, but i ntermetallic transient phases (e.g. Cu 6Sn 5) were not at all observed at the Cu-Sn interface irrespective of the applied current densitie...

The intense anodic action of sacrificial zinc pigments ensured viable galvanic function of the hi... more The intense anodic action of sacrificial zinc pigments ensured viable galvanic function of the highly porous liquid zinc-rich paints (ZRPs) result in deteriorated long-term corrosion resistance often accompanied by cathodic delamination phenomena. In our approach, such a efficacy problem related to the corrosion preventive function of ZRPs is addressed by the application of intimately structured anodic inhibitor particles composed of nano-size alumina and either polyelectrolyte-modified or chemically functionalized multi-walled carbon nanotubes (MWCNT) supported polypyrrole (PPy) in one specific zinc-rich hybrid paint formulation providing balanced active–passive protective functionality. High dispersity of the nanotube-free PPy-deposited inhibitor particles (PDIPs) with uneven polymer distribution on the alumina carrier was confirmed by transmission electron microscopy (TEM) observations. Furthermore, the MWCNT-embedded PDIPs indicated almost complete surface coverage of the alumin...

An experimental study has been carried out on the surface characteristics of hot-dip aluminized (... more An experimental study has been carried out on the surface characteristics of hot-dip aluminized (HDA) C45 carbon steel. The coated specimens were also tested thrice by cycling heat between the ambient temperature and 700°C inside an electrical resistance furnace. Both the as-coated and the oxidized samples were analyzed by scanning electron microscopy, energy dispersive spectrometry, and elemental mapping. Microstructural features and other important characteristics (compositional changes, chemical elemental distributions, growth of the intermetallic phases, the formation of micro-voids, etc.) were investigated. Under the high temperature tested conditions, the HDA coated C45 carbon steel close-to-surface top-layer almost entirely converted to iron-aluminum intermetallics, with Fe to Al atomic ratios of 1 to 2 corresponding to the phases FeAl and FeAl2. However, the innermost intermetallic phase (FeAl) formed between the finger-like structure and the steel substrate appeared quite c...

Vehicles often operate in rather harsh and even extreme environmental conditions, so their many p... more Vehicles often operate in rather harsh and even extreme environmental conditions, so their many parts all should resist well against corrosion, wear and other outer impacts, which surface phenomena need continuous developments and frequent testing. One rather fast and quite effective surface analytical technique is the Glow Discharge Optical Emission Spectrometry (GD OES), the applicability of which is demonstrated here by its several laboratory uses to detect the elementary composition in depth of some contaminated then plasma cleaned, pre-treated then metal and/or organic coated (painted or varnished) or just properly surface modified samples originating from different segments of automotive manufacturing or disassembled cars put under maintenance and/or repair.

In recent years the use of inhibitors in producing high performance concrete has increased signif... more In recent years the use of inhibitors in producing high performance concrete has increased significantly as a result of chloride and sulphate attacks. The effectiveness of an organic inhibitor extracted from a cheap organic waste of orange peel (so-called „green” inhibitor) was added to the fresh concrete. Two types of superplasticizers (Mapei Dynamon SR 31 and Oxydtron) were also used to reduce the water during concrete hardening. Then the concrete samples were immersed partially in 3.5%NaCl aqueous solutions for six months and every two weeks the corrosion potentials of the samples were regularly measured against a saturated calomel electrode. Results showed that the samples with Oxydtron had better ability to resist corrosion than the samples prepared with Mapei Dynamon SR 31, and samples with green inhibitor had less negative corrosion potentials (and even less with increasing concentration of inhibitor) than that of the reference sample (0% inhibitor).

Materials Science Forum, 2012

Nowadays the most commonly used baths for hot-dip galvanizing are the ones which contain about 0.... more Nowadays the most commonly used baths for hot-dip galvanizing are the ones which contain about 0.1 ... 0.2% of aluminium. Besides aluminium, the effects of the addition of small quantities of titanium (up to 0.0005%) to the bath have recently been studied in detail by Culcasi et al. [2]. They proved the strong impact of adding a small amount of titanium on the development of the iron-zinc layer, which influences primarily the building up of the intermetallic compound film Fe2Al5 on the surface of the steel piece in contact with the molten zinc. This aluminium-alloyed hot-dip bath with titanium usually does not form a nicely coloured surface [. Therefore, our experiments were limited to test only the effect of adding titanium to the molten zinc which contains only traces of aluminium in order to study the impact of titanium on surface colouring using GD-OES spectrometry.

The Journal of Physical Chemistry, 1989