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Powder Metallurgy Preparation of Co-Based Alloys for Biomedical Applications

100%

Marek I., Novák P., Mlynár J., Vojtěch D., Kubatík T., Málek J.

Acta Physica Polonica A

2015

vol. 128

issue 4

597-601

Co-based alloys represent very important group of materials used for medical applications. Currently, fabrication of these materials is preferentially done by casting or forming. Production by powder metallurgy techniques is less common. However, powder metallurgy fabrication of these alloys brings advantages such as reduced machining, possibility of alloying by high-melting elements, preparation of nanocrystalline materials with enhanced mechanical properties or producing of porous alloys with improved ability to integrate into issues. In this work, our attention was focused on fundamental preparation of an CoCrMo alloy by two methods of powder metallurgy. In the first method, pure metallic powders were mixed, pressed and sintered in vacuum furnace. The second applied technology consisted of mechanical alloying using planetary ball mill and compaction by spark plasma sintering technique. A series of samples was prepared under various conditions by these procedures. Dependence of microstructure, phase composition and mechanical properties of prepared samples on fabrication conditions (milling parameters, sintering temperature etc.) was studied. Obtained results were compared with properties of commercial cast cobalt alloy used for medical applications.

Preparation of Iron Nanoparticles by Selective Leaching Method

100%

Michalcová A., Vojtěch D., Kubatík T., Stehlíková K., Brabec F., Marek I.

Acta Physica Polonica A

2015

vol. 128

issue 4

640-642

Iron nanoparticles were prepared by selective leaching method. Initially the rapidly solidified AlFe11 alloy was prepared and consequently the aluminium matrix was dissolved from this alloy in 20% NaOH solution. This process was carried out at 0 and 80°C. At lower temperature, the iron nanoparticles covered by thin layer of Fe(OH)₃ were successfully obtained. The size of formed nanoparticles was about 8 nm and the particles exhibited massive agglomeration. It is not limitation of the process, because the application of nanoparticles is as a precursor for production of bulk nanocrystalline materials (metals, alloys and metal matrix composites). At higher temperature, the selective leaching process failed and iron was oxidized to different hydroxides. Aluminium containing waste liquid from selective leaching was used for production of powder Al₂O₃. Initial alloys and products were characterized by X-ray diffraction, scanning electron microscopy, and high resolution transmission electron microscopy.

Effect of Heating Rate on the Formation of Intermetallics during SHS Process

84%

Novák P., Michalcová A., Školáková A., Průša F., Kříž J., Marek I., Kubatík T., Karlík M., Haušild P., Kopeček J.

Acta Physica Polonica A

2015

vol. 128

issue 4

561-563

Self-propagating high-temperature synthesis is a simple and efficient method for the synthesis of various compounds including ceramics and intermetallics. In this process, the compressed mixture of elemental or master alloy powders is ignited or heated to initiate the exothermic reactions leading to the formation of desired compounds. In order to control the process efficiently, the effect of several important parameters has to be determined in each applied alloy system. Previous results showed that those parameters are: initiation temperature, process duration, pressure used for compression and heating rate. This paper is devoted to the description and explanation of the effect of the heating rate on the formation of intermetallics during self-propagating high-temperature synthesis in Fe-Al and Ni-Ti systems. Differential thermal analysis of compressed powder mixtures under various heating conditions and microstructure observation of samples prepared by various heating rates using electric resistance heating and spark plasma sintering were carried out. The effect of heating rates on the formations of intermetallics in studied systems is discussed in this paper.

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3 Acta Physica Polonica A

3 2015

3 Kubatík T.

3 Marek I.

2 Michalcová A.

2 Novák P.

2 Vojtěch D.

1 Brabec F.

1 Haušild P.

1 Karlík M.

1 Kopeček J.

1 Kříž J.

1 Mlynár J.

1 Málek J.

1 Průša F.

1 Stehlíková K.

1 Školáková A.

Search results

Powder Metallurgy Preparation of Co-Based Alloys for Biomedical Applications

Preparation of Iron Nanoparticles by Selective Leaching Method

Effect of Heating Rate on the Formation of Intermetallics during SHS Process