Corrosion Behavior of Some Steels in Ionic Liquids Based on Choline Chloride

2018 ◽  
Vol 69 (10) ◽  
pp. 2642-2647 ◽  
Author(s):  
Elena Ionela Neacsu ◽  
Virgil Constantin ◽  
Cristina Donath ◽  
Kazimir Yanushkevich ◽  
Aliona Zhivulka ◽  
...  

The corrosion behaviour of special steels (OL44, OL52, SS1.4571) exposed to choline chloride (ChCl) based ionic liquids, has been investigated by polarization curves method at 80�C. Micrographic images before and after corrosion were obtained. The corresponding corrosion parameters in ChCl-Oxalic acid and ChCl-Malonic acid were calculated. The crystal structure was studied before and after the corrosion process by using X-ray diffraction method. The specific magnetization was investigated by ponderomotive method.

2019 ◽  
Vol 70 (8) ◽  
pp. 2968-2972
Author(s):  
Elena Ionela Neacsu ◽  
Virgil Constantin ◽  
Cristina Donath ◽  
Kazimir Yanushkevich ◽  
Aliona Zhivulka ◽  
...  

The corrosion behaviour of special alloys (Uranus B6 steel and Monel 400) exposed to chlorine chloride-deep eutectic solvents (DES) at 353 K has been investigated by polarization curves method. The corresponding corrosion parameters in choline chloride-oxalic acid and choline chloride-malonic acid were calculated. Micrographic images before and after immersion in the corrosive medium were obtained. Measurements of the influence of the corrosion process on the crystal structure and specific magnetization of the studied steels was carried out by using X-ray diffraction and respectivelly ponderomotive methods.


2019 ◽  
Vol 33 (12) ◽  
pp. 1950111 ◽  
Author(s):  
Mihai Todica ◽  
Zoltan Kovacs-Krauss ◽  
Carmen Niculaescu ◽  
Marieta Mureşan-Pop

The modification of local structure of some commercial polyethylene terephthalate (PET) samples, gamma irradiated at different doses, was investigated by X-ray diffraction method before and after thermal treatment. Before the thermal treatment, the samples exposed to different doses of gamma radiations, does not show noticeable structural changes. However, the gamma exposure affects the thermal behavior of samples submitted to melting–cooling process. These modifications have been highlighted by X-ray diffraction, and confirmed also by thermal analysis and electron spin resonance spectroscopy.


2021 ◽  
Author(s):  
Joanna Hrabia-Wiśnios ◽  
Beata Leszczyńska-Madej ◽  
Marcin Madej ◽  
Aleksandra Węglowska

Abstract The paper presents the results of research on the microstructure and selected mechanical properties of the SnSbCu bearing alloy after friction stir processing (FSP). The Whorl tool was used for modification; the process was carried out using two rotational speeds of the tool: 280 and 450 RPM and a constant linear speed of 355 mm/min. Microstructure studies were performed employing the techniques of light microscopy and scanning electron microscopy along with analysis of the chemical composition of micro-areas. Additionally, the phase composition was investigated by means of the X-ray diffraction method and statistical analysis of the precipitates present in the investigated alloy. In addition, hardness, flexural strength and uniaxial compression tests were performed before and after FSP modification. It was proved that using FSP to modify the SnSbCu alloy promotes refinement and homogenization of the microstructure, as well as improvement of the flexural strength, whereas no changes in the hardness level were found.


Author(s):  
Elena G. Petrova ◽  
Yana A. Shavshukova ◽  
Dzmitry A. Kotsikau ◽  
Kazimir I. Yanushkevich ◽  
Konstantin V. Laznev ◽  
...  

Thermal treatment of ferrite magnetic nanoparticles in NaCl matrix gives an opportunity to increase their specific magnetization with preservation of nanoscale size. Composite materials based on mixed ferrites Co0.65Zn0.35Fe2O4 and Mg 0.5Zn0.5Fe2O4 were synthesized by spray-drying of aqueous suspensions in presence of NaCl and annealed at 300 –900 °C. The microstructure and phase composition of nanoparticles before and after annealing were studied by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction analysis and IR spectroscopy. The magnetic properties of nanoparticles were estimated using a ponderomotive method of measuring the specific magneti zation at room temperature in a magnetic field with an induction of 0.86 T. The increase of the annealing temperature up to 900 °C was established to lead to the increase in the specific magnetization of ferrites – from 32.79 to 91.3 emu/g (Co0.65Zn0.35Fe2O4) and from 2.76 to 22.31 emu/g (Mg 0.5 Zn 0.5Fe2O4) due to recrystallization processes and increase of crystallinity degree of the ferrites. Due to the NaCl insulating layer, the particle size increases just slightly (from ~ 10 nm before annealing to ~ 60 nm after annealing at 900 °C). This method is effective for substantial increase in specific magnetization of ferrite nanoparticles with preservation of their nanoscale size.


2014 ◽  
Vol 8 (4) ◽  
pp. 185-193 ◽  
Author(s):  
Amr Abdelghany ◽  
Fatema Elbatal ◽  
Hatem Elbatal

Ternary soda lime borate glass and samples with ZnO replacing CaO up to 10mol%were prepared and studied for their bone bonding ability. Fourier transform infrared (FTIR) absorption spectra of the prepared glasses before and after immersion in simulated body fluid (SBF), for one or two weeks, showed the appearance of calcium phosphate (hydroxyapatite (HA)) which is an indication of bone bonding ability. X-ray diffraction patterns were measured for the glasses and indicated the presence of small peaks related to hydroxyapatite in the samples immersed in SBF. The glasses were heat treated with controlled two-step regime to convert them to their corresponding glass-ceramic derivatives. FTIR and X-ray diffraction measurements of the glass-ceramic samples (before and after immersion in SBF) confirmed the appearance of HA which is influenced by ZnO content. The overall data are explained on the basis of current views about the corrosion behaviour of borate glasses including hydrolysis and direct dissolution mechanism.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Alexander D. Pogrebnjak

Nanostructured coatings of (Ti-Zr-Hf-V-Nb)N were obtained by the Cathodic Arc Vapor Deposition (CAVD) method. To investigate these coatings, a number of complementary methods of elemental and structural analysis were used, namely, slow positron beam (SPB), proton microbeam (μ-PIXE), micro- and nanoelectron beam (EDS and SEM analyses), and X-ray diffraction method (XRD), including method of “α-sin2φ” measurement of a stress-strain state (X-ray strain measurement). Additionally, the texture of coatings before and after annealing up to 873 K (for time of annealingτ=30 min) was also investigated. It was shown that increasing of stress-strain state in the coating during deposition increases the resistance to oxidation at high temperatures of annealing. It was also found that the redistribution of elements and defects, as well as their alignment (segregation), appeared due to thermally stimulated diffusion. It is also connected with the process of spinodal segregation near grain boundaries and interfaces around the grains and subgrains.


Author(s):  
Joanna Hrabia-Wiśnios ◽  
Beata Leszczyńska-Madej ◽  
Marcin Madej ◽  
Aleksandra Węglowska

AbstractThe paper presents the results of research on the microstructure and selected mechanical properties of the SnSbCu-bearing alloy after friction stir processing (FSP). The Whorl tool was used for modification; the process was carried out using two rotational speeds of the tool: 280 and 450 RPM and a constant linear speed of 355 mm/min. Microstructure studies were performed employing the techniques of light microscopy and scanning electron microscopy along with analysis of the chemical composition of micro-areas. Additionally, the phase composition was investigated by means of the X-ray diffraction method and statistical analysis of the precipitates present in the investigated alloy. In addition, hardness, flexural strength, and uniaxial compression tests were performed before and after FSP modification. It was proved that using FSP to modify the SnSbCu alloy promotes refinement and homogenization of the microstructure, as well as improvement of the flexural strength, whereas no changes in the hardness level were found.


Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.


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