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Development of open-porosity magnesium foam produced by investment casting

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Journal of Magnesium and Alloys 2022年第7期10卷 1941-1956页

作者： Honorata Kapłon carsten blawert Jacek Ch˛ecmanowski Krzysztof Naplocha Faculty of Mechanical Engineering Wrocław University of Science and TechnologyUl.Smoluchowskiego 25Wrocław 50-370Poland Institute of Surface Science Helmholtz-Zentrum GeesthachtMax-Planck-Straβe 1Geesthacht21502Germany Faculty of Chemistry Wrocław University of Science and TechnologyWybrze˙ze Stanisława Wyspia´nskiego 27Wrocław50-370Poland

High-porosity,open-cell AZ91 magnesium alloy foams of two pore sizes were fabricated by means of investment casting technology,using PUR foam *** casting variables such as pressure,mould temperature and metal pouring temperature were thoroughly investigated to define the most optimal casting *** mechanical properties of the fabricated foams were measured in compression tests.A potential application for the foams considered is temporary bioresorbable bone implants,therefore the mechanical properties of the foams were compared with those of cancellous bone *** with smaller pore size and lower porosity(20 PPI and 80%±87%)exhibited mechanical properties in the lower regions of the cancellous bone property range(Young’s modulus 36.5±77.5 MPa),while foams with higher pore size and porosity(10 PPI and~90%)were found to have insufficient compression strength(Young’s modulus 11.65±23.8),but thickening their walls and lowering their porosity below 90%yielded foams with Young’s modulus between 36.5 and 77.5 *** fractures were also investigated to determine their collapse mechanism.A series of corrosion tests in stimulated body fluid was carried out to determine their applicability as a *** Plasma Electrolytic Oxidation(PEO)process was used in a feasibility study to examine the microstructure and chemical composition of foams with protective coating.

关键词： Magnesium foams AZ91 investment casting Bone implants Plasma electrolytic oxidation

Corrosion performance,corrosion fatigue behavior and mechanical integrity of an extruded Mg4Zn0.2Sn alloy

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Journal of Materials Science & Technology 2020年第24期59卷 107-116页

作者： Pingli Jiang carsten blawert Jan Bohlen Mikhail L.Zheludkevich Magnesium Innovation Centre-MagIC Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck Str.1Geesthacht 21502Germany Faculty of Engineering University of KielKaiserstrasse 224143 KielGermany

Magnesium alloys are promising as load bearing *** are inevitably exposed to cyclic loading and corrosive environment in actual service,which can consequently result in corrosion fatigue failure and loss of mechanical integrity of the ***,in the present study,the corrosion behavior,corrosion fatigue performance and mechanical integrity of an extruded Mg4Zn0.2Sn(wt.%)alloy were thoroughly studied in two corrosive *** localized corrosion occurred when the alloy was immersed in deionized water based sodium chloride(NaCl)*** poor corrosion resistance of the alloy resulted in a fast deterioration of the tensile properties after pre-exposure to salt spray and a poor fatigue resistance in deionized water based NaCl *** comparison,the active dissolution of the substrate was sufficiently suppressed in artificial tap water based NaCl solution due to the formation of highly protective corrosion product *** consequently conferred longer fatigue life on the alloy in the *** results emphasized the influence of corrosion on the fatigue behavior and tensile properties of magnesium alloys.

关键词： Magnesium alloy Tin Artificial tap water Corrosion fatigue Mechanical integrity

Difference in formation of plasma electrolytic oxidation coatings on MgLi alloy in comparison with pure Mg

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Journal of Magnesium and Alloys 2021年第5期9卷 1745-1760页

作者： Ting Wu carsten blawert Xiaopeng Lu Maria Serdechnova Mikhail L.Zheludkevich Institute of Surface Science Helmholtz-Zentrum Hereon21502 GeesthachtGermany Shenyang National Laboratory for Materials Science Northeastern University110819 ShenyangChina Institute for Materials Science Faculty of EngineeringKiel UniversityKaiserstrasse 224143 KielGermany

In order to study the substrate lattice structure(Li addition)on the growth of plasma electrolytic oxidation(PEO)coatings,Mg Li alloy(11.36 wt.%of Li,cubic)and pure Mg(hexagonal)were treated under a pulsed direct PEO mode in a phosphate electrolyte for different periods of *** results revealed that the presence of Li and Li-rich phases in the cubic Mg alloy seems to be essential for the treatment result rather than the original lattice structure.A modified discharge behavior of Mg Li alloy finally led to a different microstructure of the *** unstable coatings of Mg Li alloy tended to dissolve rapidly though shared the similar composition to that of pure *** was incorporated only in the primary conversion products at the interface of coating/Mg *** spite of the advanced efficiency of energy input during processing,the more porous and thinner PEO coatings on the Mg Li alloy were less resistant to abrasion and corrosion.

关键词： Plasma electrolytic oxidation Magnesium lithium alloy Pure magnesium Microstructure

Recycling of magnesium drive train components

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Science China(Technological Sciences) 2009年第1期52卷 148-154页

作者： Daniel FECHNER carsten blawert Norbert HORT Karl Ulrich KAINER MagIC-Magnesium Innovation Centre GKSS Research Centre Max-Planck-Straβe 1

With the development of new heat resistant magnesium alloys, the automotive industry has introduced several parts to the drive train. The rising number of large magnesium components will result in a higher quantity of automotive post consumer scrap. It was the aim of this work to find a reasonable alloy system for the recycling of these magnesium drive train components. A matrix of potential recy-cling alloys based on the magnesium alloy AM50 was prepared via permanent mould casting. The materials were investigated via tensile testing, creep tests and salt spray tests. Three alloys were selected for processing via high pressure die casting and the tests were repeated on the new materials. A promising system for recycling has been isolated and will be investigated more deeply for the influence of impurities.

关键词： magnesium recycling end-of-life vehicles recycling alloy post consumer scrap

Corrosion Protection of AM50 Magnesium Alloy by Nafion/DMSO Organic Coatings

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 204-206页

作者： SONG Renguo ZHENG Xiaohua BAI Shuju blawert carsten DIETZEL Wolfgang The MOE Key Laboratory of Mechanical Manufacture and Automation Zhejiang University of Technology Hangzhou 310014 China Tieling Base Property Company of NEPPC Tieling 112001 China Institute of Materials Research GKSS-Forschungszentrum Geesthacht GmbH Geesthacht D-21502 Germany

The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid （DMSO） organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and morphologies of the Nafion/DMSO organic coatings were studied by electrochemical corrosion testing and optical microscopy. The results show that Nafion/DMSO organic coatings can improve the corrosion resistance of AM50 magnesium alloy effectively. Also, the corrosion resistance increases with the surface density of the organic coatings.

关键词： corrosion protection magnesium alloy organic coatings

As-cast and extruded Mg-Zn-Ca systems for biodegradable implants:Characterization and corrosion behavior

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Journal of Magnesium and Alloys 2023年第3期11卷 1102-1120页

作者： Lara Moreno Endzhe Matykina Kiryl A.Yasakau carsten blawert Raul Arrabal Marta Mohedano Departamento de Ingeniería Química y de Materiales Facultad de Ciencias QuímicasUniversidad Complutense de Madrid28040 MadridSpain Department of Materials and Ceramic Engineering CICECO-Aveiro institute of materialsUniversity of Aveiro3810-193 AveiroPortugal Institute of Surface Science Helmholtz-Zentrum HereonMax-Planck Strasse 1Geesthacht 21502Germany

The aim of the present study is to evaluate the effect of alloy processing and composition as well as the pH control and testing medium on the in vitro corrosion performance of Mg-Zn-Ca systems for biodegradable *** grain size and secondary phases were analyzed by optical microscopy,scanning electron microscopy,transmission electron microscopy,and X-ray *** kelvin probe force microscopy(SKPFM)was used to analyze the Volta potential values of the second *** corrosion performance of the three alloys was evaluated by electrochemical and hydrogen evolution methods inα-MEM with and without organic species(*** and inorganicα-MEM).Two strategies were followed to evaluate the influence of the pH on the corrosion behavior:daily solution replacement and CO_(2)flow based pH *** all the materials,the organic medium accelerates the corrosion *** pH maintained by CO_(2)flow through the medium results in considerably higher corrosion rates for all *** impact of pH is lesser on the as-cast alloys due to the barrier effect of the secondary phases,particularly pronounced in the Mg1Zn1Ca alloy which showed the lowest corrosion *** wrought Mg0.5Zn0.2Ca alloy that lacks the refined secondary phase network and exhibits high number of twins undergoes accelerated uniform corrosion under constant pH conditions.

关键词： MgZnCa Magnesium Biomaterials Characterization Corrosion

Self-cleaning property of AZ31 Mg alloy during plasma electrolytic oxidation process

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Progress in Natural Science:Materials International 2019年第1期29卷 94-102页

作者： Jiaping Han carsten blawert Junjie Yang Xiaopeng Lu Jin Hu Mikhail L.Zheludkevich National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and Engineering Harbin Institute of Technology Magnesium Innovation Centre-MagIC Institute of Materials Research Helmholtz-Zentrum Geesthacht Corrosion and Protection Division Shenyang National Laboratory for Materials Science Northeastern University

The rolling of metal sheet often leads to strong contamination of the resulting surface. The present work reports the effects of the surface contamination remaining after rolling of AZ31 Mg alloy on plasma electrolytic oxidation(PEO) treatment of the resulting sheet material. Results indicate that most of the contaminants on the surface of as-rolled AZ31 Mg alloy are removed in the early stages of PEO process. The contaminations slightly influence the phase composition of PEO coating. Non-uniform distribution of contaminations results in aggregation of pores on the surface of PEO samples. On the bare substrate the contaminations are responsible for poor wear and corrosion resistance but final PEO coatings reveals similar performance on contaminated substrate compared to the abraded one. A self-cleaning property of the PEO and possibility of one step process,avoiding pre-cleaning stages, is suggested.

关键词： Intermetallics Mechanochemical processing Corrosion Electrochemical impedance spectroscopy Scanning electron microscopy

Nafion/polypyrrole and Nafion/DMSO Organic Coatings for Magnesium Protection

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Journal of Materials Science & Technology 2007年第1期 141-143页

作者： carsten blawert Wolfgang Dietzel Center for Magnesium Technology Institute of Materials ResearchGKSS-Forschungszentrum Geesthacht GmbHMax-Planck Straβe 1D-21502 GeesthachtGermany

Nafion/polypyrrole and Nafion/Dimethysulfoxid (DMSO) organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.

关键词： Magnesium Naflon/polypyrrole organic coatings Nafion/DMSO organic coatings Corrosion resistance

Effect of low concentration electrolytes on the formation and corrosion resistance of PEO coatings on AM50 magnesium alloy

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Journal of Magnesium and Alloys 2024年第4期12卷 1386-1405页

作者： Peng Xie carsten blawert Maria Serdechnova Natalia Konchakova Tatsiana Shulha Ting Wu Mikhail L.Zheludkevich Institute of Surface Science Helmholtz-Zentrum HereonMax-Planck Strasse 121502 GeesthachtGermany Institute for Materials Science Faculty of EngineeringKiel UniversityKaiserstrasse 224143 KielGermany

In this paper,the formation process,morphology,and electrochemical performance of PEO coatings on AM50 magnesium alloy prepared in low concentration phosphate,aluminate,and phosphate-aluminate electrolytes were systematically *** results show that the coatings prepared from the phosphate electrolytes have a higher thickness and better corrosion resistance properties compared to the other *** coatings prepared from low concentration phosphate-aluminate mixed electrolytes have slightly thinner thickness,a similar coating structure and an order of magnitude lower value of electrochemical impedance compared with phosphate electrolyte *** Coatings prepared from low concentration aluminate electrolytes have the lowest thickness and the worst corrosion resistance properties which gets close to corrosion behavior of the bare AM50 under the same test *** application,coatings prepared from single low concentration phosphate electrolytes and low concentration phosphate-aluminate electrolytes have greater potential than single low concentration aluminate ***,reducing the electrolyte concentrations of coating forming ions too much has negative influence on the coating growth rate.

关键词： Plasma electrolytic oxidation Low concentration electrolytes Corrosion resistance AM50 magnesium alloy