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1

Manufacturing Cu-Pb alloys and studying efficiency in resisting oxidation

Sufian Amina, Hamood Mahmood Ahmad Al- Jiboori

Ochrona przed Korozją

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2023

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nr 12

388--392

EN

Binary alloys of copper and lead were produced by casting these elements in specially designed moulds with dimensions appropriate to the tests to be carried out on them. The effectiveness of these alloys in resisting oxidation was then studied in an atmosphere of a mixture of sodium chloride vapour and sodium sulphate at specific concentrations and heating the mixture to 180°C. Recently, corrosion has become a major problem in the overall performance of many engineering devices due to automotive exhaust gases produced by the internal combustion engine, which leads to corrosion of materials that make up some components of engineering industries. Copper also has good corrosion performance due to the formation of a copper oxide layer, which has made it the most important material in industrial applications. Through this research, we have achieved the desired goal as the alloys produced have shown their efficiency in resisting saline and acidic conditions and at high levels. The best sample is Cu95Pb5 and Cu90Pb10 with little difference between them in terms of efficiency. The aim of this work is to produce alloys and study their efficiency in resisting oxidation at high temperatures.

PL

Binarne stopy miedzi i ołowiu zostały wytworzone metodą odlewania w specjalnie zaprojektowanych formach o wymiarach dostosowanych do badań. Odporność stopów na utlenianie została zbadana w atmosferze mieszaniny oparów chlorku sodu i siarczanu sodu w określonych stężeniach i po podgrzaniu mieszaniny do 180°C. Korozja jest poważnym problemem, zaburza funkcjonowanie wielu urządzeń inżynieryjnych. Jej źródłem są m.in. spaliny wytwarzane przez silniki spalinowe. Miedź ma dobre właściwości antykorozyjne ze względu na warstwę tlenku miedzi, tworzącą się na jej powierzchni w wyniku utleniania. Z tego względu jest głównym materiałem stosowanym w przemyśle. Badane stopy miedzi i ołowiu wykazały wysoką odporność na działanie soli i kwasów w dużych stężeniach. Najlepsze wyniki uzyskano dla stopów Cu95Pb5 i Cu90Pb10 (różnica między nimi była niewielka). Celem pracy było zbadanie odporności wytworzonych stopów na utlenianie w wysokich temperaturach.

2

Degradation of pulp mill wastewater by a heterogeneous Fenton-like catalyst Fe/Mn supported on zeolite

Wang Y., Shia S., Wang C., Fanga S.

Environment Protection Engineering

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2018

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Vol. 44, nr 2

131--145

EN

A novel heterogeneous catalyst, Fe/Mn supported on NaY zeolite, was effectively applied for treating pulp mill effluents. The results of the wastewater quality analysis showed that aromatic structures were present in raw pulp mill effluents, which indicated the difficulty for biodegradation treatments. Two different catalysts were prepared by impregnation (Fe-Mn/NaYim) and sol-gel (Fe-Mn/NaYsg) methods, respectively. The Fe-Mn/NaYsg catalyst demonstrated higher COD removal efficiency and was more stable than the Fe-Mn/NaYim catalyst. The synergistic effects were found between Fe and Mn for COD removal. The highest COD removal efficiency (75.2%) was yielded with the Fe-Mn/NaYsg catalyst (Fe/Mn molar ratio of 2) with 4 mmol/dm3 of H2O2 and 1.2 g/dm3 of catalyst addition. A constant COD removal over time was obtained; the COD removal efficiency amounted to 45% after the Fe-Mn/NaYsg catalyst repeatedly degrading pulp mill effluents for five times. The distribution and transformation of the polarity and molecular weight (MW) of dissolved organic carbon (DOC) in the heterogeneous Fenton process were also studied. Experiments showed that the hydrophobic fraction comprised the largest fraction of DOC (60%) in raw wastewater and high MW molecules were transformed into low MW molecules after the heterogeneous Fenton process. This study broadened the application of the Fenton technology.

3

ThermoCalc Application for the Assessment of Binary Alloys Non-Equilibrium Solidification

Zyska A., Konopka Z., Łągiewka M., Kordas P.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

163--168

EN

The paper presents the possibility of application of the developed computer script which allows the assessment of non-equilibrium solidification of binary alloys in the ThermoCalc program. The script makes use of databases and calculation procedures of the POLY-3 module. A solidification model including diffusion in the solid state, developed by Wołczyński, is used to describe the non-equilibrium solidification. The model takes into account the influence of the degree of solute segregation on the solidification process by applying the so-called back-diffusion parameter. The core of the script is the iteration procedure with implemented model equation. The possibility of application of the presented calculation method is illustrated on the example of the Cr-30% Ni alloy. Computer simulations carried out with use of the developed script allow to determine the influence of the back-diffusion parameter on the course of solidification curves, solidus temperature, phase composition of the alloy and the fraction of each phase after the solidification completion, the profile of solute concentration in liquid during solidification process, the average solute concentration in solid phase at the eutectic temperature and many other quantities which are usually calculated in the ThermoCalc program.