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Corrosion Behaviour Correlation of the Secondary Aluminium Casts in Natural Atmosphere and Laboratory Conditions

Kuchariková L., Liptáková T., Tillová E., Bonek M., Medvecká D.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 4

1455--1462

EN

The secondary aluminium alloys are very important material in actual industry from economic and ecological point of view. The secondary aluminium used for production of casts, however, contains some elements, i.e. iron, – affecting physical, chemical and mechanical behaviour. The subject of our investigation has been corrosion behaviour in natural atmosphere of the hypoeutectic AlSi7Mg0.3 cast alloys with various content of iron, because the Fe content affects not only mechanical properties but corrosion resistance, as well. Three types of the AlSi7Mg0.3 cast alloys were exposed for 9 months in natural atmosphere and the measure of their degradation by corrosion was found by determination of the weight loss and the light microscopy. In addition, a scanning electron microscopy (SEM) analyses and evaluation of surface changes were used. The corrosion behaviour in natural atmosphere was compared to results of the carried out electrochemical and exposure laboratory experiments in chloride solutions.

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Material parameters affecting degradation processes of Al-brasses in pipe systems

Liptáková T., Lovíšek M., Hadzima B., Dundeková S.

Archives of Materials Science and Engineering

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2015

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Vol. 76, nr 1

27--34

EN

Purpose: As construction material of cooling pipe systems there are often used Al-brasses because their high thermal conductivity, mechanical workability and corrosion resistance. In the pipes liquid media of various chemical compositions are flowing by different rates. It means that the material is loaded mechanically also chemically what results in synergy effect on degradation. Susceptibility to corrosion-erosion damage of four Al-brasses manufactured by different producers is investigated because in operation conditions they have different reliability and lifetime. Design/methodology/approach: By studying of their microstructure, surface state, selected mechanical properties and corrosion characteristics the parameters which affected chemicalmechanical degradation were evaluated. Experimental methods are SEM, EDX and spectral analyses, measurement of microhardness and roughness. Findings: By actual obtained results it was identified that in spite of very similar chemical composition differences in mechanical and corrosion behaviour are affected by technology of manufacturing. It can explain their different durability in operating conditions. Research limitations/implications: To identify more precisely the main parameters important for degradation resistance in various flow media the original experimental device is designed and constructed. The device makes possible to test Al-brasses in various flowing media by the same mail at three flowing rates. By long time lasted experiments in the one it is able to simulated operation specification. Results of the device are not presented yet because they are just in progress. Practical implications: Obtained results will be very helpful for choice of Al-brasses for required operation conditions according important properties which were experimentally verified. Originality/value: It means contribution to economy by material saving in operation by available choice and design and construction of original experimental device.

3

Variations of temperature of acrylic bone cements prepared by hand and vacuum mixing during their polymerization

Liptáková T., Lelovics H., Nečas L.

Acta of Bioengineering and Biomechanics

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2009

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Vol. 11, nr 3

47-51

EN

The aim of this work was to investigate variations of temperature in acrylic bone cement SmartSet HV during its polymerization as the function of mixing technique (hand mixing and vacuum mixing) and sample thickness. The temperature of 25-mm diameter samples differing in their thickness was monitored using a parallel plate measuring system of the compact rheometer preheated to the body temperature. The curves representing the temperature measured and average values of times needed to obtain the peak temperatures of the test samples prepared by different techniques of mixing are presented and discussed. It was found that the maximum temperature and also the times of peak temperatures rose with sample thickness but at different rate for each technique of mixing.