Study of structure formation in aluminum filled polytetrafluoroethylene after explosive compression

2021 ◽  
pp. 26-32
Author(s):  
Nina Adamenko ◽  
Andrej Kazurov ◽  
Dmitry Savin ◽  
Galina Agafonova ◽  
Keyword(s):  
Structure Formation ◽  
Adhesive Bond ◽  
Metal Particles ◽  
Polymer Layer ◽  
Aluminum Fluoride ◽  
Interfacial Separation ◽  
Static Pressing ◽  
Explosive Pressing

The features of the structure formation in polytetrafluoroethylene filled with 10 and 30% (vol.) aluminum after static and explosive pressing have been studied. It was revealed that after static pressing during sintering, interphase separation occured, which is confirmed by the formation of structures of the «closed buds» type. After explosive pressing with sintering, fibrils between polytetrafluoroethylene and aluminum and a polymer layer covering metal particles were found, and there was no interfacial separation that indicates the formation of a strong adhesive bond and is confirmed by the formation of aluminum fluoride.

scholarly journals STUDY OF THE STRUCTURE OF HIGHLY FILLED FLUOROPLAST-ALUMINUM COMPOSITES

2020 ◽  
pp. 25-29
Author(s):  
N. A. Adamenko ◽  
A. V. Kazurov ◽  
D. V. Savin ◽  
G. V. Agafonova ◽  
A. S. Ageikin
Keyword(s):  
Structure Formation ◽  
Metal Particles ◽  
Aluminum Composites ◽  
Monolithic Material ◽  
Adhesive Interaction ◽  
Metal Frame ◽  
Static Pressing ◽  
Dispersed Aluminum ◽  
Explosive Pressing

Structure formation in fluoroplastic-aluminum composites obtained by static and explosive pressing has been investigated. The concentration of dispersed aluminum was 50 and 70% vol. In fluoroplastic-aluminum composites, after static pressing, spalling of metal particles, formed during the preparation of a microsection, was found, which indicates low adhesion of the polymer and metal. The production of fluoroplastic-aluminum composites using explosive pressing leads to the formation of a monolithic material with a high adhesive interaction of the components and the formation of a metal frame.

scholarly journals RESEARCH OF FEATURE OF STRUCTURE FORMATION IN PTFE-ALUMINUM COMPOSITE MATERIALS DURING SINTERING

2020 ◽  
pp. 42-46
Author(s):  
N. Adamenko ◽  
A. Kazurov ◽  
D. Savin ◽  
G. Agafonova
Keyword(s):  
Composite Materials ◽  
Structure Formation ◽  
Free Volume ◽  
Closed Volume ◽  
Aluminum Composite ◽  
Interfacial Separation ◽  
Lower Porosity ◽  
Static Pressing ◽  
Dispersed Aluminum

The structure formation in fluoroplastic-aluminum composite materials during sintering after static pressing was studied. The concentration of dispersed aluminum was 30% vol.. After sintering, interfacial separation was observed in the fluoroplastic-aluminum composite materials, which is formed during crystallization due to shrinkage, which indicates a low adhesion of the filler to the polymer. Sintering of composite materials in a closed volume leads to the formation of a material with a lower porosity than when sintering in a free volume.

scholarly journals Enhancement the Properties of Construction Urea Composition with Polymer Additive

2021 ◽  
Vol 2 (2) ◽  
pp. 1-8
Author(s):  
Arslanov Islom Kimsanovich
Keyword(s):  
Structure Formation ◽  
Building Materials ◽  
Chemical Resistance ◽  
Adhesive Bond ◽  
Alkali Resistance ◽  
Scientific Article ◽  
Strength Increase ◽  
Polymer Additive ◽  
Water Binding ◽  
Acid And Alkali Resistance

This scientific article provides physicochemical studies where the addition of a gel polymer has a positive effect on the process of structure formation. The presence of chemical bonds between the components, a change in the morphology of the structure, a decrease in microporosity, an increase in the density and thermal stability of the urea composition are shown. Polymer composite materials are used as chemically resistant coatings, polymer mortars and polymer concretes. Along with such valuable properties as incombustibility, colorlessness, good miscibility with water, etc., urea resins and compositions based on them have a number of disadvantages. The object of the study is a carbamide composition with a quartz filler and an addition of a gel polymer, its structure formation and chemical resistance. The methodological basis of the study is the polystructural theory of composite building materials (CBM) and the modeling of the study of the chemical resistance of the urea composition in aggressive conditions. The issues of finding effective water-binding additives and studying their effect on structure formation, properties and technology of urea compositions remain relevant and require additional research. It is shown that with the optimal content of the gel-polymer additive in the composition of 0.13% of the filler weight, the compressive strength and specific impact strength increase by 17; 13% and shrinkage is reduced by 7%. It was found that due to the enhancement of the adhesive bond between the components and the improvement of the pore structure under the action of the gel-polymer additive, the chemical resistance of the urea composition with quartz filler increases. So, water, acid and alkali resistance are 0.75; 0.80 and 0.85 and which, respectively, are 6, 7 and 7 points higher than the reference composition.

scholarly journals STUDY OF THERMOMECHANICAL PROPERTIES OF UHMWPE

2021 ◽  
pp. 30-33
Author(s):  
N. A. Adamenko ◽  
G. V. Agafonova ◽  
D. A. An ◽  
A. V. Kazurov ◽  
V. S. Pirozhenko
Keyword(s):  
Molecular Weight ◽  
Heat Resistance ◽  
Graphite Powder ◽  
High Heat ◽  
Thermomechanical Properties ◽  
High Heat Resistance ◽  
Similar Material ◽  
Ultra High Molecular Weight ◽  
Static Pressing ◽  
Explosive Pressing

The paper presents comparative studies of the thermomechanical properties of ultra-high molecular weight polyethylene (UHMWPE) and its composite containing 0.5% coke-graphite powder (CGP). It was found that explosive pressing with a pressure of 0.25-0.6 GPa provides high heat resistance of UHMWPE and the investigated composite (154-156 ° C). The heat resistance of the composite decreases to 143-145 ° C, but it is higher than that of a similar material after static pressing (128 ° C).

Structure Formation in Nickel-Polytetrafluorethylene Composite Materials upon Explosive Pressing of Powders

2020 ◽  
Vol 11 (4) ◽  
pp. 982-990
Author(s):  
N. A. Adamenko ◽  
A. V. Kazurov ◽  
G. V. Agafonova ◽  
D. V. Savin
Keyword(s):  
Composite Materials ◽  
Structure Formation ◽  
Explosive Pressing

Electron Microscopy of the Shape of Small Metal Particles

1977 ◽  
Vol 35 ◽  
pp. 300-301
Author(s):  
M. Jose Yacaman
Keyword(s):  
Electron Microscopy ◽  
Metal Particle ◽  
Field Experiments ◽  
Size Range ◽  
Dark Field ◽  
Metal Particles ◽  
Bragg Condition ◽  
Crystal Particle ◽  
Small Metal Particle ◽  
Small Metal Particles

In the Study of small metal particles the shape is a very Important parameter. Using electron microscopy Ino and Owaga(l) have studied the shape of twinned particles of gold. In that work electron diffraction and contrast (dark field) experiments were used to produce models of a crystal particle. In this work we report a method which can give direct information about the shape of an small metal particle in the amstrong- size range with high resolution. The diffraction pattern of a sample containing small metal particles contains in general several systematic and non- systematic reflections and a two-beam condition can not be used in practice. However a N-beam condition produces a reduced extinction distance. On the other hand if a beam is out of the bragg condition the effective extinction distance is even more reduced.

Structure and composition of metal particles in Pt-Sn/Al2O3 bimetallic catalysts

1990 ◽  
Vol 48 (4) ◽  
pp. 278-279
Author(s):  
A. Sachdev ◽  
J. Schwank
Keyword(s):  
Bimetallic Catalysts ◽  
Bimetallic Catalyst ◽  
Size Structure ◽  
High Surface ◽  
High Surface Area ◽  
Metal Particles ◽  
Alloy Formation ◽  
Particle Size Range ◽  
Oxide Supports ◽  
Petroleum Fractions

Platinum - tin bimetallic catalysts have been primarily utilized in the chemical industry in the catalytic reforming of petroleum fractions. In this process the naphtha feedstock is converted to hydrocarbons with higher octane numbers and high anti-knock qualities. Most of these catalysts contain small metal particles or crystallites supported on high surface area insulating oxide supports. The determination of the structure and composition of these particles is crucial to the understanding of the catalytic behavior. In a bimetallic catalyst it is important to know how the two metals are distributed within the particle size range and in what way the addition of a second metal affects the size, structure and composition of the metal particles. An added complication in the Pt-Sn system is the possibility of alloy formation between the two elements for all atomic ratios.

Investigation of cluster layers of small netal particles by TEM, SEM, EELS and by photoacoustic spectroscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 250-251
Author(s):  
H. Seiler ◽  
U. Haas ◽  
K.H. Körtje
Keyword(s):  
Bulk Material ◽  
High Vacuum ◽  
Optical Methods ◽  
Metal Particles ◽  
Silver Particles ◽  
Low Loss ◽  
Plasmon Excitation ◽  
First Results ◽  
Diffraction Patterns ◽  
Small Metal Particles

The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared silver layers evaporated in high vacuum with cluster layers of small silver particles, evaporated in N2 at a pressure of about 102 Pa. The investigations were performed by electron optical methods (TEM, SEM, EELS) and by Photoacoustic (PA) Spectroscopy (gas-microphone detection).The observation of cluster layers with TEM and high resolution SEM show small silver particles with diameters of about 50 nm (Fig. 1 and Figure 2, respectively). The electron diffraction patterns of homogeneous Ag layers and of cluster layers are similar, whereas the low loss EELS spectra due to plasmon excitation are quite different. Fig. 3 and Figure 4 show first results of EELS spectra of a cluster layer of small silver particles on carbon foil and of a homogeneous Ag layer, respectively.

Coherent electron nanodiffraction from clean silver nano particles in a UHV STEM

1993 ◽  
Vol 51 ◽  
pp. 1058-1059
Author(s):  
J. Liu ◽  
M. Pan ◽  
G. E. Spinnler
Keyword(s):  
Supported Catalysts ◽  
Imaging Techniques ◽  
Nano Particles ◽  
Metal Particles ◽  
Shape Structure ◽  
Dynamical Simulations ◽  
Small Metal Particles ◽  
Extract Information

Small metal particles have peculiar chemical and physical properties as compared to bulk materials. They are especially important in catalysis since metal particles are common constituents of supported catalysts. The structural characterization of small particles is of primary importance for the understanding of structure-catalytic activity relationships. The shape and size of metal particles larger than approximately 5 nm in diameter can be determined by several imaging techniques. It is difficult, however, to deduce the shape of smaller metal particles. Coherent electron nanodiffraction (CEND) patterns from nano particles contain information about the particle size, shape, structure and defects etc. As part of an on-going program of STEM characterization of supported catalysts we report some preliminary results of CEND study of Ag nano particles, deposited in situ in a UHV STEM instrument, and compare the experimental results with full dynamical simulations in order to extract information about the shape of Ag nano particles.

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