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Abstract

U-type ferrite typified by Ba4Co2Fe36O60 is used as a RAM (Radar Absorbing Materials) in the X-band (8-12 GHz). Ba4Co2Fe36O60 is known to have a complex crystal structure, which makes it difficult to obtain single phase and have low reproducibility. Previously known U-type ferrites have been fabricated based on a ceramic process that mixing (by a ball mill), calcining, grinding, binder mixing, drying, sieving, pressing and sintering. In contrast, the process of preparing the powder by the sol-gel method and its heat-treating is advantageous in that it can reduce the process steps and the required time. In addition, the precise stoichiometric control by the sol-gel method can effectively evaluate the effect of added or substituted elements. In this study investigates the crystal structure of Ba4Co2Fe36O60 synthesized by the sol-gel method and the morphology of U-type ferrite nano-powders according to various heat treatment conditions. Analysis of the crystal structure is used for XRD. Morphology and size are observed by SEM. In addition, VSM is performed to confirm the change of magnetic properties according to various heat treatment conditions.

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Authors and Affiliations

K.-P. Jeong
S.-W. Yang
J.-G. Kim
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Abstract

The paper contains the results of the initial surface treatment influence on the properties of the medical Ti-6Al-7Nb alloy with a modified zirconium oxide layer deposited on its surface by sol-gel method. In the paper, the analysis of results of potentiodynamic studies is presented as well as its resistance to pitting corrosion and electrochemical impedance spectroscopy (EIS), macroscopic observation of the surface of samples and analysis of geometrical structure with the use Atomic Force Microscope (AFM) were performed. The studies were performed on two groups of samples depending on the graduation of the sand used in sandblasted process – 50 μm and 250 μm. Based on the obtained results it can be concluded that the type of the initial surface treatment preceding the surface modification of the Ti-6Al-7Nb has a significant effect on its properties.

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Authors and Affiliations

A. Woźniak
B. Ziębowicz
A. Ziębowicz
W. Walke
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Abstract

The paper presents the influence of ZrO2 coating on Ti6Al7Nb titanium alloy depending on the method of deposition. The coatings were made by sol-gel method and atomic layer deposition (ALD). Wettability tests, pitting corrosion assessment and electrochemical impedance spectroscopy (EIS) were carried out in the paper. Complementary macro- and microscopic observations, roughness analysis by profilometric method and atomic force microscopy (AFM) were made. Based on the results obtained, it can be concluded that the type of method of depositing the layer on the surface of the material has a significant influence on its properties and that it should be taken into account during the process of the material improvement. Drawing on the findings presented, it can be inferred that roughness has a significant impact upon the surface wetttability of the tested surfaces and their related corrosion resistance. The obtainment of hydrophobic surfaces is for smaller rougidity values.

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Authors and Affiliations

A. Woźniak
O. Bialas
M. Adamiak

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