scholarly journals Method for the modification of graphite subsurface layer to a solid mixture of SiC and graphite

2021 ◽  
Vol 2086 (1) ◽  
pp. 012012
Author(s):  
A S Grashchenko ◽  
S A Kukushkin ◽  
A V Osipov ◽  
A V Redkov

Abstract We studied the interaction of molten Si and graphite surface during annealing in different atmospheres (CO, vacuum, Ar). The studies have shown that during annealing in CO atmosphere a composite material of SiC and graphite in a thick subsurface layer of the graphite is being formed, whereas at vacuum and Ar atmosphere the modified layer is either thin or absent. The composition and structure of both the composite material itself and the interface between the composite material and the graphite matrix were investigated using the methods of scanning electron microscopy and Raman spectroscopy. Studies have shown that the composite material obtained by this method has a branched fibrous structure consisting of small tubular layers of silicon carbide interspersed with large monocrystalline grains of silicon carbide of the cubic polytype, which leads to significant strengthening of the material. Thus the proposed method can be used to form a thermal protective, chemically resistant coating on graphite surface.

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.


2012 ◽  
Vol 706-709 ◽  
pp. 271-276 ◽  
Author(s):  
Claudia Carrasco ◽  
C. Montalba ◽  
Carlos Camurri

In the present study, the fabrication of an Al-based metal matrix composite material obtained directly from the melting of the aluminium used beverage cans in a modified rheocasting process is presented. The analysed operational condition is the shear rate applied to the bath and its influence on the properties of the obtained samples. Additionally, samples were heat treated at two different times. The characterization of the phases obtained in Al-based MMC was made by means of metallography, scanning electron microscopy with energy dispersive spectroscopy and electron microprobe with wavelength dispersion spectroscopy. The results show that some constituents were formed during the fabrication process of the MMC, mainly Al6(Fe, Mn), which are partially transformed during the heat treatment. Additionally, samples were evaluated using dynamic mechanical analysis, and the results suggest that the obtained MMC could have very good mechanical properties, similar or superior to the aluminium alloys commonly used for structural applications such as 6XXX family.


2018 ◽  
Vol 243 ◽  
pp. 00017 ◽  
Author(s):  
Daria Goncharova ◽  
Ekaterina Gavrilenko ◽  
Anna Nemoykina ◽  
Valery Svetlichnyi

The paper studies physicochemical and antibacterial properties of ZnO nanoparticles obtained by pulsed laser ablation in water and air. Their composition and structure were studied by X-ray diffraction, transmission and scanning electron microscopy. Antibacterial activity of the nanoparticles was examined by its affection on Gram-positive Staphylococcus aureus (S.aureus). The dependence of nanoparticles’ physical and chemical antibacterial properties on the conditions of the ablation was shown. The model materials for the antibacterial bandage were made of cotton, filter paper and biodegradable polymer scaffolds (poly-l-lactide acid), and then they were coated with the obtained ZnO nanoparticles. The model bandage materials were examined by the scanning electron microscopy method and their antibacterial activity (ISO 20743:2013) was determined. High activity of all the samples against S.aureus was proved.


2013 ◽  
Vol 12 (4) ◽  
pp. 095-105
Author(s):  
Beata Klimek

One of the main tasks in the study of historic buildings is the need to identify the original materials and extensions, which often have historic character. The next task concerns the determination of the composition and structure of the historical, diagnosis technique to develop original paint. The article presents the preliminary results of paintings. Methods were used with the scanning electron microscope was equipped with an energy dispersive X-ray spectrometer (SEM-EDS).


2015 ◽  
Vol 5 (01) ◽  
pp. 31
Author(s):  
Resky Irfanita ◽  
Asnaeni Ansar ◽  
Ayu Hardianti Pratiwi ◽  
Jasruddin J ◽  
Subaer S

The objective of this study is to investigate the effect of sintering temperature on the synthesis of SiC produced from rice husk ash (RHA) and 2B graphite pencils. The SiC was synthesized by using solid state reaction method sintered at temperatures of 750°C, 1000°C and 1200°C for 26 hours, 11.5 hours and 11.5 hours, respectively. The quantity and crystallinity level of SiC phase were measured by means of Rigaku MiniFlexII X-Ray Diffraction (XRD). The microstructure of SiC was examined by using Tescan Vega3SB Scanning Electron Microscopy (SEM). The XRD results showed that the concentration (wt%) of SiC phase increases with the increasing of sintering temperature. SEM results showed that the crystallinity level of SiC crystal is improving as the sintering temperature increases


Author(s):  
Md Mehtab Alam and B.S Motgi

The paper deals with detailed study on microstructure and mechanical properties of aluminum 7068 reinforced with fly ash and silicon carbide by powder metallurgy, aluminum 7068, silicon carbide and fly ash were taken in powder form of required size and mixed together in varying proportion according to specification and compacted with pressure of 400MPa using hydraulic press to make samples and then samples were sintered at 600°c for 2 hours, the samples were tested for density, compressive strength, hardness and microstructure was analyzed using scanning electron microscope, energy dispersive x-ray study was carried out in order to confirm presence of silicon carbide and fly ash in aluminum matrix.


2013 ◽  
Vol 378 ◽  
pp. 213-219
Author(s):  
Byunh Hyun Ahn ◽  
Dong Gun Lee ◽  
Je Hyun Lee ◽  
Uk Rae Cho ◽  
Bon Heun Koo

AlON-Al2O3coatings were prepared on Al2021 alloy by the electrolytic plasma processing (EPP) method. NaNO2, NaNO3and NH4NO3were chosen as nitrogen supply agents. The nitrogen inducing effect was studied by a combined composition and structure analysis of the coating layer carried out by X-ray diffractometer (XRD), scanning electron microscopy (SEM) for the specimens EPP-treated at room temperature for 15 min under a hybrid voltage of 260V DC plus 200V AC (50Hz) power. Microhardness tests and wear tests were carried out to correlate the evolution of microstructure and resulting mechanical properties.


2021 ◽  
pp. 39-46
Author(s):  
A.V. Gololobov ◽  
◽  
A.N. Nyafkin ◽  
A.N. Zhabin ◽  
◽  
...  

A metal composite material (MCM) based on an aluminum corrosion-resistant alloy of the AMg6 brand, containing 22.5 % (vol.) Silicon carbide, obtained by mechanical alloying, has been investigated. Aspects of the formation of the MCM structure based on chips and powder from this alloy are considered. The influence of the initial components on the structure of the dispersion-strengthened MCM was investigated, and samples were made from this composite material.


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