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Ded J.,Ustav Kovovych materialu a korozniho inzenyrstvi | Hosek J.,Archeologicky ustav AV CR Prague v. v. i | Ottenwelter E.,Archeologicky ustav AV CR Prague v. v. i | Stefan I.,Ustav pro ranou dobu dejinnou FF UK
Journal of Marine Science and Application | Year: 2012

This contribution is focused on the typological, material and technological study of a set of fifty five S-shaped temple rings found in the excavations of an early medieval cemetery in Vrbno (distr. Mělník). The goals of the study were to identify the different types of S-shaped temple rings present in the set, and to highlight the different techniques used in their manufacture. The temple rings were characterized by observation under optical stereomicroscope and scanning electron miscroscope (SEM), supplemented by the results of non-destructive analyses by X-Ray Fluorescence spectrometry (XRF) and electron microanalysis (EDX). The results have shown that most of the temple rings were made of copper with small amounts of tin, lead and zinc although some were made of almost pure copper and a few of low zinc brass with some arsenic. Investigation also revealed that some temple rings were plated with tin, silver or gold. © Archeologický ústav AV ÈR, Praha, v.v.i.

Novikova D.,Ustav Kovovych Materialu A Korozniho Inzenyrstvi | Kouril M.,Ustav Kovovych Materialu A Korozniho Inzenyrstvi | Msallamova S.,Ustav Kovovych Materialu A Korozniho Inzenyrstvi | Stoulil J.,Ustav Kovovych Materialu A Korozniho Inzenyrstvi | Strnadova N.,Ustav Technology Vody A Prostredi
Koroze a Ochrana Materialu | Year: 2016

Concentrating of pore bentonite water as a result of water evaporation at the hot container surface is expected when the bentonite cover of the permanent nuclear waste container is being gradually saturated. The study assesses the influence of an extent of the pore water enrichment by chloride and sulphate ions up to a multiple of a hundred of their equilibrium concentration. An increase of concentration of these ions does not imply an increase of the electrolyte aggressivity automatically. A minimum of corrosion resistance was observed at triplicate concentration at all temperatures, 40, 70 and 90°C. Even more significant impact on corrosion behaviour was recognized for composition of anoxic atmosphere above the electrolyte. Contrary to nitrogen, the mixture of nitrogen and carbon dioxide remarkably elevates the electrolyte's corrosion aggressivity. © by M. Kouřil 2016.

Svadlena J.,Ustav Kovovych Materialu A Korozniho Inzenyrstvi | Boryskova S.,Kabinet Restaurovani Fotografie FAMU
Koroze a Ochrana Materialu | Year: 2015

Unsuitable storage conditions and use of materials which may be a source of pollutants in indoor environments are major threats to the long-term preservation of historic metal objects. Materials proposed for use in protecting and storage of museum or archive collections need to be sufficiently verified in terms of safety for the protected objects before these materials can be safely recommended. One of the basic techniques used for the purpose of testing of new materials (and verifying of those that are already in use) is the Oddy test whose advantages lies in its simple requirements for the experimental equipment and a possibility to modify this method for a particular use. In this work, a variant of the Oddy test was applied with a modification for a specific case - evaluation of materials used for recasing of daguerreotypes. Besides the commonly used visual assessment, electrochemical reduction of corrosion products on the exposed samples was used to compare the Oddy test results. The results indicate that the influence of the test materials is minor compared to the influence of the state of the daguerreotypes surface. This conclusion is consistent with expectations about safety of the tested materials that are used in conservation practice for the protection of archival and historical photographic collections.

Formanek J.,Ustav Kovovych Materialu a Korozniho Inzenyrstvi | Jandova J.,Ustav Kovovych Materialu a Korozniho Inzenyrstvi | Sis J.,SVUM a.s.
Chemicke Listy | Year: 2012

The aim of the study is to review hydrometallurgical and partly pyrometallurgical technologies of the Zn and Mn recovery from spent Zn/MnC 2 batteries. Main attention was devoted to basic hydrometallurgical operations such as leaching, precipitation, solvent extraction and electrolysis, which are described in patents and literature. Compared with pyrometallurgical processes, hydrometallurgy is a well-established and efficient method for the recovery of not only Zn and Mn but also other battery components such as steel, plastics and paper.

Novak P.,Ustav kovovych materialu a korozniho inzenyrstvi
Chemicke Listy | Year: 2012

This review summarizes recent research of intermetallics in the Department. The research is focused on hightemperature materials, shape memory alloys and hydrogen storage materials. In the case of high-temperature intermetallics, the development of TiAl-Ti5Si3 and NiAl-Al2O3 composites and Fe-Al-Si alloys is described. Powder metallurgy using reactive sintering has been established as an innovative and promising method for easy preparation of the materials. This method is currently tested and optimized for NiTi shape memory alloys. In the case of NiTi alloys for medicinal implants, surface treatment was developed to improve their corrosion resistance in body fluids and biocompatibility. Another important property of intermetallics (such as LaNi5 or Mg2Ni) is their ability to reversibly store hydrogen. In hydrogen storage, hydrides (e.g. Mg2NiH4) are formed. Hydrogen can be released from the materials by heating. The current aim is to develop an easy and efficient method of hydrogen storage and to to lower the hydrogen release temperature.

Pecenova Z.,Ustav Kovovych Materialu A Korozniho Inzenyrstvi | Kouril M.,Ustav Kovovych Materialu A Korozniho Inzenyrstvi
Koroze a Ochrana Materialu | Year: 2016

Historical lead artefacts (small figurines, appliques, bull (metal seal) can be stored in depository and archives in inconvenient storage conditions. The wooden show-case or paper packagings release volatile organic compound to the air during their degradation. These acids, mainly acetic acid are very corrosive for lead. The thin layer of corrosion products which slows atmospheric corrosion is formed on lead surface in atmospheric condition. In presence of acetic acid vapour the voluminous corrosion products are formed and fall off the surface. These corrosion products do not have any protection ability. The lead could be protected against acid environment by layer of "metal soup" which is formed on surface after immersion in solution of salt of carboxylic acid for 24 hours. The solutions of acids (with vary long of carbon chain) and their salts are examined. Longer carbon chain provides better efficiency convers layer. The disadvantages are low solubility of carboxylic acids in water and bad abrasion resistance of formed layer. © 2016 Pecenová Z. et al.

Moravec H.,Ustav kovovych materialu a korozniho inzenyrstvi | Fojt J.,Ustav kovovych materialu a korozniho inzenyrstvi | Filip V.,Ustav kovovych materialu a korozniho inzenyrstvi | Joska L.,Ustav kovovych materialu a korozniho inzenyrstvi
Chemicke Listy | Year: 2014

Ti implants have become an important instrument in handling various problems associated with the loss of flexibility of a joint system. Having replaced a damaged joint with an endoprosthesis reduces pain, restores flexibility and improves the patient's quality of life. The implantbone integration may be a complicated and lengthy process. Therefore, the state of the material surface is of vital importance. Ti can be treated electrochemically to produce a tubular nanostructure, which can later be modified to achieve bioactivity. Moreover, the large adsorption surface enables anchoring of biologically active substances and pharmaceuticals. The nanostructure and its further modifications could facilitate and strengthen the implant-bone integration, and thus shorten the healing process. The article describes the preparation of nanostructures and summarizes the knowledge of Ti surface treatment.

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