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Wyszukujesz frazę "graphite" wg kryterium: Temat


Tytuł:
Effect of Bismuth and Rare Earth Elements on Graphite Structure in Different Section Thicknesses of Spheroidal Graphite Cast Iron Castings
Autorzy:
Glavas, Z.
Strkalj, A.
Maldini, K.
Kozina, F.
Powiązania:
https://bibliotekanauki.pl/articles/353810.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spheroidal graphite cast iron casting
graphite structure
bismuth
rare earth elements
microstructure
Opis:
Effects of additions of 0.00064, 0.001 and 0.0042 wt.% Bi on the graphite structure in the section thicknesses of 3, 12, 25, 38, 50, 75 and 100 mm of spheroidal graphite cast iron castings containing 2.11 wt.% Si and rare earth (RE) elements (Ce + La + Nd + Pr + Sm + Gd) in the range from 0.00297 to 0.00337 wt.% were analyzed in this paper. Addition of Bi was not necessary for obtaining high nodule count and nodularity higher than 80% in section thicknesses of 3, 12 and 25 mm. RE elements showed a beneficial effect on the nodule count and nodularity in these sections. Nodularity was below 80% in section thicknesses of 38, 50, 75 and 100 mm when Bi was not added. Detrimental effect of RE elements on graphite morphology in these sections was neutralized by adequate addition of Bi. Addition of 0.001 wt.% Bi (ratio of RE/Bi = 3.27) was enough to achieve nodularity above 80% in the section thickness of 38 mm. Nodularity was increased above 80% in section thicknesses of 50, 75 and 100 mm by addition of 0.0042 wt.% Bi (ratio of RE/Bi = 0.78). At the same time, Bi significantly increased the nodule count. Nodularity above 80% and the high nodule count in the section thicknesses of 75 and 100 mm were also achieved by using an external metallic chill in the mold. In this case, addition of Bi was not required.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1547-1553
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observation of spheroidal graphite in ductile cast iron by TEM
Charakterystyka grafitu w żeliwie sferoidalnym techniką transmisyjnej mikroskopii elektronowej
Autorzy:
Hara, T.
Maekawa, T
Terayama, K
Kawabata, T.
Ikeno, S.
Matsuda, K.
Powiązania:
https://bibliotekanauki.pl/articles/354792.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ductile cast iron
spheroidal graphite
TEM
FIB method GRAPHITE
grafit sferoidalny
technika FIB
transmisyjna mikroskopia elektronowa
Opis:
The microstructure of spheroidal graphites in ductile cast iron (FCD450) was investigated by TEM using cross sectional TEM samples prepared by FIB method. The spheroidal graphite consisted of many small areas, and all of these areas were indexed as the graphite structure and just carbon peak was detected from there.
Mikrostruktura sferoidalnych wydzieleń grafitu w żeliwie sferoidalnym (FCD450) badana była przy użyciu transmisyjnej mikroskopii elektronowej i cienkich folii przygotowanych technika FIB. Grafit sferoidalny składał się z wielu małych obszarów i stwierdzono, że wszystkie te obszary mają strukturę grafitu i wykryto tylko pik od wegla.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 2; 431-432
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Manganese on the Crystallisation Process, Microstructure and Selected Properties of Compacted Graphite iron
Autorzy:
Gumienny, G.
Kurowska, B.
Just, P.
Powiązania:
https://bibliotekanauki.pl/articles/354354.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compacted graphite iron
crystallization
manganese
DTA method
Opis:
The paper presents the effect of manganese on the crystallization process, microstructure and selected properties: cast iron hardness as well as ferrite and pearlite microhardness. The compacted graphite was obtained by Inmold technology. The lack of significant effect on the temperature of the eutectic transformation was demonstrated. On the other hand, a significant reduction in the eutectoid transformation temperature with increasing manganese concentration has been shown. The effect of manganese on microstructure of cast iron with compacted graphite considering casting wall thickness was investigated and described. The nomograms describing the microstructure of compacted graphite iron versus manganese concentration were developed. The effect of manganese on the hardness of cast iron and microhardness of ferrite and pearlite were given.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 4; 1269-1275
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nickel in Compacted Graphite Iron
Autorzy:
Gumienny, G.
Kurowska, B.
Szymczak, T.
Gawroński, J.
Powiązania:
https://bibliotekanauki.pl/articles/352803.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compacted graphite iron
crystallization process
DTA method
Opis:
The paper presents results of the research work concerning effects of nickel concentration on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in the cast iron was obtained with use of the Inmold process. The study has comprised the cast iron containing nickel up to concentration providing obtainment of austenitic microstructure of the matrix. The effect of the nickel on temperature of the eutectic crystallization was specified. It has been presented composition of the cast iron matrix in function of nickel concentration in a casting with wall thickness of 3 mm and 24 mm. Moreover, it has been presented conditions defining the possibility of obtaining an austenitic and martensitic compacted graphite iron. Effect of the nickel on hardness of the cast iron was described.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 657-662
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wear Mechanism of Spheroidal Cast Iron Piston Ring-Aluminum Matrix Composite Cylinder Liner Contact
Autorzy:
Bąkowski, H.
Powiązania:
https://bibliotekanauki.pl/articles/352888.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cast iron
spheroidal graphite
wear mechanism
stereological parameters
Opis:
The paper presents the results of research on the impact of stereological characteristics of microstructure of graphite in nodular GJS-400 cast iron and Al2 O3 fibers in the composite AC-47000 + 10% Al2 O3 F on the mechanism of wear in a cast iron piston ring – composite cylinder liner contact in a combustion engine. To elucidate the mechanisms of wear in the tested contact was used Finite Element Method (FEM). On the basis of quantitative metallographic examination of test materials were determined stereological parameters of their structures. It was necessary for the implementation of the 3D model that reflects the actual structure with particular focus on the different phases in order to determine the distribution of stresses and strains. The determination Strains of the local stresses value of allowed the prediction of wear initiating places. Formation of stereological parameters of cast iron in the technological process allows a prediction of values and distributions of the stresses/strains and thus reduce wear and extend durability of the analyzed contact.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 481-490
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Microstructure of Grey Cast Irons by Electrical Resistivity Measurements
Autorzy:
Petrič, M.
Mrvar, P.
Kastelic, S.
Powiązania:
https://bibliotekanauki.pl/articles/354044.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification
grey cast iron
electrical resistivity
graphite shape
microstructure
Opis:
The paper describes the influence of graphite shape, size and amount to electrical properties of different cast irons. Experiments of electrical resistivity measurements were conducted during solidification of four different melts in different time intervals from melt treatment by inoculation and nodularization. Metallographic analyses were made in order to determine the shape, size, distribution and amount of graphite and correlate results with electrical resistivity measurements. It was found out that nodular graphite is giving the lowest electrical resistivity and is decreased during solidification. Electrical resistivity of lamellar cast iron is increased during solidification since lamellas interrupt metal matrix severely. There is no significant difference in resistivity of vermicular cast iron from nodular cast iron. Smaller size of graphite and lower amount of graphite and higher amount of metal matrix also decrease resistivity.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 1; 365-369
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected the Casting Properties of the Composites AlMg10+Cgr
Autorzy:
Łągiewka, M.
Powiązania:
https://bibliotekanauki.pl/articles/355986.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium alloys
metal composites
graphite particles
castability
surface tension
Opis:
The paper is a review of the previous investigations concerning the influence of graphite particles both on the casting properties of metal matrix composites (MMCs). The work presents the examination results of casting properties (i.e. castability and shrinkage) of the MMCs with matrices of a selected aluminium alloy reinforced with graphite particles. There is also presented the influence of graphite particles on the surface tension and viscosity of the flowing and filling the mould composite suspension. The suspensions containing various percentages of graphite particles (namely 5%, 10%, or 15% in volume) were prepared in order to perform the above mentioned examinations. Castability (fluidity) of these suspensions was measured in two ways, i.e. by means of both the spiral test and the rod test, while their shrinkage was determined with the use of a device designed and assembled in the Department of Foundry Engineering, CUT. The device enables to determine changes in the length of a casting during its solidification with respect to the specified length of the test rod. The surface tension was determined by the wedge casting method consisting in the pouring of metal into an open shell mould with the cavity of wedge geometry, the sharp edge being perpendicular to the free metal surface. The change in viscosity corresponding to the change in graphite particles percentage was calculated from Einstein’s equation. The results of examinations show that the introduction of reinforcing graphite particles results in both a significant increase in the viscosity of the flowing suspension and a considerable decrease in its castability. The greater dimensional stability of castings was observed, i.e. the shrinkage of composite castings was smaller than the shrinkage of matrix alloy itself. An increase in surface tension index value with an increase in volume percentage of graphite particles in composite was also noticed.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1585-1589
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cast Hybrid Composites Designated for Air Compressor Pistons
Autorzy:
Dolata, A. J.
Dyzia, M.
Jaworska, L.
Putyra, P.
Powiązania:
https://bibliotekanauki.pl/articles/356742.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid aluminium composites
glassy carbon
graphite particles
mould casting
machining
Opis:
The main purpose of the investigations was to develop the phase composition of the composite assuming that the component selection criterion will be the formability of piston work surfaces during the machining. Wear resistance under the friction conditions was assumed as the additional parameter for the assessment of composite material. In the study were used AlSi7Mg/SiC+Cg and AlSi7Mg/SiC+GR hybrid composites prepared by the stir casting method.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 705-708
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Chunky Graphite in Nodular Cast Iron on the Base of Numerical Simulation and Experimental Data
Autorzy:
Bauer, B.
Mihalic Pokopec, I.
Petrič, M.
Mrvar, P.
Powiązania:
https://bibliotekanauki.pl/articles/352270.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chunky graphite
nodular cast iron
numerical simulation
cooling curve
microstructure
Opis:
Chunky graphite has been recognized for a long time as one of the major problems in production of heavy section nodular cast iron. A great number of studies have been conducted to describe the chunky graphite formation, but a clear understanding of its appearance and a safe mastering of the melt preparation to avoid chunky graphite are not yet available. In the present work the cooling curves were recorded in large cone blocks and standard TA cup. According to measured data from the cone block, melt characteristics and heat transfer coefficient between casting and mould were adjusted in the ProCAST® simulation software. For a near-eutectic nodular cast iron test melt with 0.7 wt.% Ni, relationship between the area of the cone block affected by chunky graphite and simulation software results has been observed, i.e., thermal modulus and time to solidus.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 1; 343-347
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Graphite - Polymer - Turbostratic Carbon Composites by Acoustic Emission Method at Perpendicular Geometry
Autorzy:
Berdowska, A.
Berdowski, J.
Aubry, F.
Powiązania:
https://bibliotekanauki.pl/articles/356589.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compressed expanded graphite
polyfurfuryl alcohol
turbostratic carbon
acoustic emission
composite membrane
Opis:
The purpose of this paper was to search the relations between the structure of the compressed expanded graphite–polymer–turbostratic carbon composites on successive stages of technological treatment and parameters describing the acoustic emission phenomena in these materials. The acoustic emission method can be used for measurements of changes in the structure and many different properties of materials. These investigations are a continuation of our earlier studies concerning physical, mechanical and chemical properties of porous composites created on the basis of a compressed expanded graphite matrix, obtained after successive technological procedures of impregnation, polymerization and carbonization of polyfurfuryl alcohol. The aim of this work was to investigate materials obtained at different levels of technological processing, thus with different densities, porosity, physical and chemical properties, by using the acoustic emission method. In compressed expanded graphite composites structures one can differentiate two basic directions: perpendicular to the bedding plane of graphite flakes and parallel to this one. The all presented results were obtained for the uniaxial strain applied in the direction perpendicular to the bedding plane of the composite structure. Analysis of acoustic emission parameters provides information on physical and chemical processes in these materials.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1287-1293
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Alloying Additions on High Temperature Interaction Between Molten Compacted Graphite Iron and Alumina
Autorzy:
Sobczak, N.
Bacior, M.
Turalska, P.
Bruzda, G.
Homa, M.
Sobczak, J. J.
Powiązania:
https://bibliotekanauki.pl/articles/354903.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compacted graphite iron
Al2O3
sessile drop method
wettability
interface
Opis:
High temperature behavior of three compacted graphite iron (CGi) alloys on polycrystalline aluminasubstrates (99.7%, porosity <3%) were examined by the sessile drop method combined with classical contact heating procedure in flowing Ar. High-speed high-resolution CCd camera was used for continuous recording of the CGi/Al2 O3 couples during melting alloy, heating to and holding the couples at the test temperature of 1450°C for 15 min and their subsequent cooling. The comparative studies were made with conventional CGi (in wt.%: 3.70 C, 2.30 Si, 0.44 Mn, 0.054 P, 0.017 Mg, 0.015 S) and two alloys additionally containing the same amounts of 0.25 Mo, 0.1 V, 0.045 Sn and 0.032 Sb with different concentrations of Mg + Cu additions, i.e. 0.01Mg + 0.33Cu and 0.02Mg + 0.83Cu. All three CGi alloys demonstrated non-wetting behavior on the Al2 O3 substrates while the contact angle values slightly decreased with increase of the Mg + Cu content in the alloy, i.e. 131° (unalloyed CGi), 130° (0.01Mg + 0.33Cu) and 125° (0.02Mg + 0.83Cu). Structural characterization of solidified couples by light microscopy and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy revealed: 1) heterogeneous nucleation of discontinuous graphite layer at the drop-side interfaces and on the surface of the drops; 2) reactively formed Mg-rich oxide layer at the substrate-side interface; 3) the formation of satellite droplets on the surface of the drops during their solidification; 4) degeneration of initially compacted graphite to lamellar graphite after remelting and subsequent solidification of the drops, particularly in their surface layer.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 3; 1227-1238
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wear resistance of graphitized steels
Odporność grafityzowanej stali na zużycie ścierne
Autorzy:
Byelikov, S
Volchok, I.
Akimov, I
Powiązania:
https://bibliotekanauki.pl/articles/351033.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
graphitized steel
graphite inclusions
wear resistance
stal grafityzowana
wydzielenia grafitu
zużycie ścierne
Opis:
Heat-treated graphitized steels with different carbon, silicon and copper contents have been the object of study. The influence of the composition on the structure and wear resistance (weight loss of the specimen) of graphitized steels (after hardening and tempering) under the conditions of metal to metal dry sliding friction with the use of Amsler-type friction machines, has been investigated in this work. Research results have shown that the main factors affecting wear resistance of graphitized steels have been not only their metal base hardness, but the quantity, shape and distribution of graphite inclusions uniformity in the structure of such steels as well. A regression dependence of the quantity of specimen’s weight loss on carbon, silicon and copper content has been obtained in the work. The highest wear resistance was pertained by the steel having the following content: 1.60. . . 1.70%C; 2.20. . . 2.30%Si; 0.80. . . 0.90%Cu; 0.60. . . 0.70%Mn; 0.15. . . 0.18%Cr; 0.22. . . 0.25%Al; up to 0.015%S and 0.024%P.
Przedmiotem badań była grafityzowana stal (po obróbce cieplnej) o zróżnicowanej zawartości węgla, krzemu oraz miedzi. W pracy przedstawiono wyniki badań wpływu składu chemicznego grafityzowanej stali, po hartowaniu i odpuszczaniu, na jej strukturę i zużycie ścierne (zmniejszenie masy próbki) w warunkach suchego tarcia ”metal-metal” na maszynie typu Amslera. Wyniki badań świadczą o tym, że odporność na zużycie ścierne zależy nie tylko od twardości osnowy metalowej, lecz także od ilości, kształtu i jednorodności wydzieleń grafitu oraz rozkładu przestrzennego wtrąceń w strukturze stali tego typu. Otrzymano zależności regresyjne wartości ubytku masy próbek w funkcji zawartości węgla, krzemu i miedzi. Największą odpornością na zużycie ścierne wyróżniają się stale o następującym składzie chemicznym: 1,60. . .1,70% C, 2,20. . . 2,30% Si, 0,80. . . 0,90% Cu, 0,60. . . 0,70% Mn, 0,15 . .. 0,18% Cr, 0,22. . . 0,25% Al, do 0,015% S i 0,024% P.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 3; 813-816
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interactions between liquid slag and graphite during the reduction of metallic oxides
Interakcje pomiędzy ciekłymi żużlami, a grafitem w trakcie redukcji tlenków metalicznych
Autorzy:
Migas, P.
Karbowniczek, M.
Powiązania:
https://bibliotekanauki.pl/articles/353333.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
redukcja żużla
grafit
ciekły żużel
zwilżanie
slag reduction
graphite
liquid slag
wettability
Opis:
High global demand for metallic elements such as Fe, Cr, Ti, Mn leads to an intensive technological development of metal recovery. One of the ways is to recover metals from metallurgical slag. The sessile drop method was adopted in order to study the interactions between liquid slag and graphite. Steelmaking slag was used during this research. The slag used included converter slag and slag from chrome steel melting as well as their mixtures with other modifiers. The analysis covered six types of slag in the temperature ranging from 1100°C to 1600°C in the argon atmosphere. In the course of research mass spectrometry and scanning microscope were used. The following were set for the examined samples during the reduction process: liquidus temperature and the nature of interactions (wettability or its lack). It was observed that the volume of slag samples dynamically changed in the course of the reduction of metallic oxides.
Duże zapotrzebowanie dzisiejszego Świata na pierwiastki metaliczne np. Fe, Cr, Ti, Mn, powoduje bardzo intensywny rozwój technologii ich odzysku m.in. z żużli metalurgicznych. Przy użyciu techniki leżącej kropli wykonano badania współoddziaływania ciekłych żużli z grafitem. Do badań wykorzystano żużle stalownicze: konwertorowy i z wytopu stali chromowych oraz ich mieszanin z innymi modyfikatorami, analizie poddano sześć żużli w zakresie temp 1100-1600°C w atmosferze argonu. W badaniach wykorzystano również spektrometr masowy oraz mikroskop skaningowy. Określono temperaturę liquidus dla analizowanych próbek, jak również charakter interakcji - zwilżanie lub jego brak - w trakcie trwania procesu redukcji. Zaobserwowano dynamiczne zmiany objętości próbek żużlowych w trakcie zachodzenia procesu redukcji tlenków metalicznych.
Źródło:
Archives of Metallurgy and Materials; 2010, 55, 4; 1147-1157
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of High-Strength Gray Cast Iron Using Permanent Magnet Scrap
Autorzy:
Park, S.-Y.
Kim, J. H.
Seo, S. J.
On, J. S.
Lim, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/352204.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gray cast iron
rare earth element
Nd-Fe-B magnet scrap
graphite formation
microstructure
Opis:
In this study, we have developed the manufacturing technology for high strength gray cast irons by using the spent permanent magnet scraps. The cast specimen inoculated by using a spent magnet scraps showed the excellent tensile strength up to 306MPa. This tensile strength value is 50MPa higher than that of the specimen cast without inoculation, and is similar to that of the specimen inoculated by using the expensive misch-metal. These superior mechanical properties are attributed to complex sulfides created during solidification that promote the formation and growth of Type-A graphite. It is therefore concluded that spent magnets scrap can provide an efficient and cost-effective inoculation agent for the fabrication of high-performance gray cast iron.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1113-1117
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlations between Structures of Expanded Graphite - Polymer Composites and Acoustic Emission Phenomena
Korelacje pomiędzy strukturą kompozytów grafit ekspandowany-polimer a zjawiskami emisji akustycznej
Autorzy:
Berdowska, A.
Berdowski, J.
Aubry, F.
Powiązania:
https://bibliotekanauki.pl/articles/355731.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compressed expanded graphite
polymer
composite
acoustic emission parameters
grafit ekspandowany
polimer
kompozyty
parametry emisji akustycznej
Opis:
Compressed expanded graphite was applied as a base matrix to the preparation of microporous composites as products of impregnation, polymerization and carbonization of poly-furfuryl alcohol. During carbonization, the original polymeric structure is transformed into an amorphous turbostratic carbon structure with ultramicropores. The structure, porosity and many chemical and physical properties change after each stage of their technological treatment. The acoustic emission method was used for accurate determination of these changes. It is possible to determine a large number of acoustic emission parameters and therefore to increase the amount of information provided by the studied materials. Acoustic emission pulses, counts rate, events rate, signal peak value and their sums were measured. Also frequency spectrum was received as a result of acoustic emission signal analysis with use of Fourier transformation procedure. The conclusions resulting from the Fourier analysis of the registered spectrum are very interesting and provide information about composite structures as well as bonds between the graphite matrix and the polymer that fills it. Analysis of acoustic emission parameters provides data on physical and chemical processes that would be very difficult to study by means of other techniques. Wide applications of these porous composites make them very interesting subject of the study.
Sprasowany grafit ekspandowany użyto jako bazową matrycę do wytworzenia mikroporowatych kompozytów będących produktami impregnacji, polimeryzacji i karbonizacji alkoholu polifurfurylowego. Podczas procesu karbonizacji oryginalna struktura polimerowa jest przekształcana w strukturę turbostratyczną węgla amorficznego z ultramikroporami. Struktura, porowatość oraz wiele chemicznych i fizycznych własności ulega zmianie na poszczególnych etapach technologicznego procesu. Metodę emisji akustycznej użyto w celu dokładnego przebadania tych zmian. Możliwym jest wyznaczenie w eksperymentach dużej liczby parametrów emisji akustycznej co pozwala uzyskać dużą ilość informacji o badanych materiałach. Zmierzono następujące parametry emisji akustycznej: szybkość zliczeń, szybkość zdarzeń, amplituda impulsu, średnia wartość skuteczna sygnałów oraz sumy tych parametrów. Także analizowano widmo częstotliwościowe sygnałów przy pomocy transformaty Fouriera. Wnioski wynikające z analizy fourierowskiej widm są niezwykle interesujące i dostarczają informacje o strukturze kompozytów oraz o wiązaniach między grafitową matrycą a polimerem wypełniającym ją. Analiza parametrów emisji akustycznej dostarcza wielu danych o fizycznych i chemicznych własnościach, które byłyby bardzo trudne do zbadania przy użyciu innych metod. Szerokie zastosowania omawianej grupy porowatych kompozytów czyni je bardzo interesującym przedmiotem badań.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 4; 2479-2484
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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