graphite content
Recently Published Documents


TOTAL DOCUMENTS

142
(FIVE YEARS 34)

H-INDEX

16
(FIVE YEARS 2)

2022 ◽  
pp. 37-44
Author(s):  
DMІTRIY NOVAK ◽  
KATERYNA MARYNIAKA

Purpose. Creation of software for evaluating the uniformity of distribution of the filler in a polyethylene matrix.Methodology. Software development was carried out using the Python programming language and libraries: PIL, Numpy, Matplotlib, Xlsxwriter. The suitability of the developed software for use was determined by verifying it. During this verification, polyethylene compositions filled with colloidal graphite in the form of compressed films were evaluated. To obtain these compositions, we chose P6006AD grade polyethylene and C-1 colloidal graphite. Samples of polyethylene compositions were obtained in two stages: 1) obtaining a strand by extrusion; 2) additional mixing of the composition on a disc mixer and pressing the obtained compositions into a film.Findings. The software has been developed to assess the uniformity of the distribution of the filler in the polyethylene matrix. The data were established on the dependence of the coefficient of heterogeneity of polyethylene compositions on the content of colloidal graphite with use of the developed software. The increase in the content of the filler leads to a decrease in its heterogeneity. It is shown that this effect can be explained by the structuring of the filler in the polyethylene matrix. Despite the formation of aggregates in polyethylene compositions, a significant amount of small colloidal particles of graphite is located between the aggregate space. This leads to a certain leveling of the concentration in the film and reduces its inhomogeneity.Scientific novelty. The influence of the content of colloidal graphite on the homogeneity of polyethylene compositions is determined. It is shown that with an increase in the graphite content from 0 to 20% vol. the coefficient of heterogeneity of the composition decreases from 5.3% to 3.9%, which is due to the structuring of the filler in the polyethylene matrix.Practical value. Software that makes it possible to evaluate the uniformity of the distribution of filler particles in a polymer matrix, and can be used to study the quality of mixing of polymer composite materials has been developed.


2021 ◽  
pp. 103057
Author(s):  
S.E. Gass ◽  
W.A. Calvo ◽  
M.N. Moliné ◽  
P.G. Galliano ◽  
A.G. Tomba Martinez

2021 ◽  
Vol 2133 (1) ◽  
pp. 012019
Author(s):  
Wentao Wang ◽  
Lisheng Zhou ◽  
Yang Li ◽  
Peng Li ◽  
Guohui Chen ◽  
...  

Abstract To improve the anti-ablative property of EPDM-based composites, nano-graphite powder as anti-ablation filler was introduced to optimize the EPDM insulation material formulas. Characterization of anti-ablation performance showed that the composite at the nano-graphite content of 10phr exhibited the best anti-ablation and mechanical performances, such as: a linear ablation rate of 0.062 mm/s, a mass ablation rate of 0.048 g/s, tensile strength of 5.69 MPa and Elongation at break of 391.2%. The nano-graphite was proven to be an effective material which is beneficial to improve the anti-ablation of the EPDM composites.


2021 ◽  
Vol 1045 ◽  
pp. 9-16
Author(s):  
Valeriy Kassov ◽  
Elena Berezshnaya ◽  
Nikolay Malyhin ◽  
Yana Antonenko ◽  
Kateryna Zubenko

The practicability of introducing a synthesized graphite compound, intercalated with oxygen, into the protection coat is grounded. The composition and the method of manufacturing a protection coat based on the oxidized graphite, which does not require preliminary preparation of the metal structures surface before welding with an open arc, have been developed. The effect of the oxidized graphite content in the composition of the protection coat on its thermal stability and thermal expansion coefficient is analyzed. The main technological characteristics of the developed protection coat have been investigated and their compliance with the basic criteria for constructing protection coats has been confirmed.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3458
Author(s):  
Wojciech Żórawski ◽  
Anna Góral ◽  
Medard Makrenek ◽  
Dominika Soboń ◽  
Anna Trelka ◽  
...  

This study analyzed the mechanical properties of cold-sprayed Cr3C2-25(Ni20Cr) blended with Ni-graphite as a solid lubricant deposited on 7075 aluminum alloy substrate. To optimize the coating properties, different sets of parameters (graphite content in feedstock, process gas composition, spraying distance, and traverse gun speed) were tested in the frame of the Taguchi experiment. The cold-sprayed coatings were evaluated for their chromium carbide and graphite content, hardness, and coefficient of friction. Analysis of the microstructure of the deposited coatings revealed that graphite as a soft and brittle component fills all voids in the coating and its quantity depends on its content in the feedstock. The experimental results show that the composition of the process gas has the greatest impact on the Cr3C2 content in the coating and the proportion of graphite in the sprayed blend directly affects its hardness. In the case of the coefficient of friction, the most significant parameters were the graphite content in the sprayed blend, the spraying distance, and process gas composition. The conducted verification experiment with the optimum parameter values allowed a coating with the highest hardness and the lowest coefficient of friction to be obtained.


2021 ◽  
Vol 58 (5) ◽  
pp. 236-263
Author(s):  
H. Rojacz ◽  
M. Premauer ◽  
A. Nevosad

Abstract Since marginal sharpness is often an issue in metallographic samples preparation, various mounting compounds are commercially available which address these issues. Nevertheless, the conductivity of such products is not sufficient for electron backscatter diffraction measurements (EBSD) and products which are electrically conductive often result in a lack of marginal sharpness. Therefore, this study is focussed on the modification of commercially available embedding compounds (epoxy based and phenolic based hot embedding compounds) with graphite to increase their electrical conductivity. To verify the applicability of the modified embedding compounds, the austenitic steel grade 1.4301 was chosen for investigation via scanning electron microscopy and EBSD. Results indicate a good performance during SEM-investigations of the epoxy-based resins, even at 0 wt.-% graphite contents, whereas the phenolic resin-based embedding compound is only applicable for SEM-investigation > wt.-5 % of graphite. Best performance at EBSD measurements were achieved with phenolic resin based hot mounting compounds with glass fibres and an addition > 10 wt.-% graphite.


2021 ◽  
Vol 144 (1) ◽  
Author(s):  
Md Syam Hasan ◽  
Amir Kordijazi ◽  
Pradeep K. Rohatgi ◽  
Michael Nosonovsky

Abstract Data-driven analysis and machine learning (ML) algorithms can offer novel insights into tribological phenomena by establishing correlations between material and tribological properties. We developed ML algorithms using tribological data available in the literature for predicting the coefficient of friction (COF) and wear-rate of self-lubricating aluminum graphite (Al/Gr) composites. We collected data on effects of material variables (graphite content, hardness, ductility, yield strength, silicon carbide content, and tensile strength), processing procedure, heat treatment and tribological test variables (normal load, sliding speed, and sliding distance) on tribological properties and established two-parameter relationships. These data are analyzed using several ML algorithms: artificial neural network (ANN), K nearest neighbor (KNN), support vector machine (SVM), gradient boosting machine (GBM), and random forest (RF). The trained ML models can predict the tribological behavior from material variables and test conditions, beyond what is possible from two-parameter correlations. GBM outperformed other ML algorithms in predicting friction behavior, while RF had the best prediction of the wear behavior. ML analysis identified graphite content and hardness and as the most significant variables in predicting the COF, while graphite content and sliding speed were the most dominant variables for wear-rates.


2021 ◽  
pp. 004051752199981
Author(s):  
Yuanjun Liu ◽  
Yi Wang ◽  
Guang Yin

In this paper, single-layer coated polyester–cotton composites were prepared using PU-2540 waterborne polyurethane resin as the adhesive, graphite and silicon carbide as functional particles, and adopting a coating technology on the plain polyester–cotton fabric. First, the single-layer graphite-coated polyester cotton composite was prepared with graphite as the functional particle, and the influence of graphite content on the reflection loss and shielding effectiveness was studied. When the applied electric field frequency is 1610 MHz and the graphite content is 40 wt%, the minimum reflection loss is −26 dB; when the applied electric field frequency is 39.9 MHz and the graphite content is 50 wt%, the maximum shielding effectiveness is 12 dB. Then the single-layer silicon carbide-coated polyester–cotton composite was prepared with silicon carbide as the functional particle, and the influence of silicon carbide content on the reflection loss and shielding effectiveness was studied. With the applied electric field in the range 500∼3000 MHz, the greater the content of silicon carbide, the smaller the reflection loss, the better the wave-absorbing ability, the larger the shielding effectiveness, and the better the shielding performance. Finally, the single-layer graphite/silicon carbide-coated polyester–cotton composites were prepared by doping graphite and silicon carbide in different proportions, and the influence of doping ratio on dielectric properties, reflection loss, and shielding effectiveness was investigated. The real part of the dielectric constant of the material was highest – that is, the polarization ability of the material was best when there were only graphite particles in the doping medium and the silicon carbide content was 0. The imaginary part of the dielectric constant and the tangent of loss angle of the material were the highest – that is, the loss and attenuation ability of the material were best – when the doping ratio of graphite to silicon carbide is 4:1. With the applied electric field in the range 500∼3000 MHz, and with increasing graphite content, the reflection loss of the material became smaller, showing an enhanced wave-absorbing property, and the shielding effectiveness of the material increased, showing an enhanced shielding performance.


Sign in / Sign up

Export Citation Format

Share Document