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1
Content available Thermoelectric properties of bismuth-doped magnesium silicide obtained by the self-propagating high-temperature synthesis
Bucholc Bartosz, Kaszyca Kamil, Śpiewak Piotr, Mars Krzysztof, Kruszewski Mirosław J., Ciupiński Łukasz, Kowiorski Krystian, Zybała Rafał
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2022
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Vol. 70, nr 3
art. no. e141007
EN
Doping is one of the possible ways to significantly increase the thermoelectric properties of many different materials. It has been confirmed that by introducing bismuth atoms into Mg sites in the Mg2Si compound, it is possible to increase career concentration and intensify the effect of phonon scattering, which results in remarkable enhancement in the figure of merit (ZT) value. Magnesium silicide has gained scientists’ attention due to its nontoxicity, low density, and inexpensiveness. This paper reports on our latest attempt to employ ultrafast self-propagating high-temperature synthesis (SHS) followed by the spark plasma sintering (SPS) as a synthesis process of doped Mg2Si. Materials with varied bismuth doping were fabricated and then thoroughly analyzed with the laser flash method (LFA), X-ray diffraction (XRD), scanning electron microscopy (SEM) with an integrated energy-dispersive spectrometer (EDS). For density measurement, the Archimedes method was used. The electrical conductivity was measured using a standard four-probe method. The Seebeck coefficient was calculated from measured Seebeck voltage in the sample subjected to a temperature gradient. The structural analyses showed the Mg2Si phase as dominant and Bi2Mg3 located at grain boundaries. Bismuth doping enhanced ZT for every dopant concentration. ZT = 0.44 and ZT=0.38 were obtained for 3wt% and 2wt% at 770 K, respectively.
2
Content available Production of High-Purity Tantalum Metal Powder for Capacitors Using Self-Propagating High-Temperature Synthesis
Lee Yong-Kwan, Sim Jae-Jin, Byeon Jong-Soo, Lee Yong-Tak, Cho Yeong-Woo, Kim Hyun-Chul, Heo Sung-Gue, Lee Kee-Ahn, Seo Seok-Jun, Park Kyoung-Tae
Archives of Metallurgy and Materials
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2021
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Vol. 66, iss. 4
935--939
EN
In this study, high-purity tantalum metal powder was manufactured via self-propagating high-temperature synthesis. During the process, Ta2O5 and Mg were used as the raw material powder and the reducing agent, respectively, and given that combustion rate and reaction temperature are important factors that influence the success of this process, these factors were controlled by adding an excessive mass of the reducing agent (Mg) i.e., above the chemical equivalent, rather than by using a separate diluent. It was confirmed that Ta metal powder manufactured after the process was ultimately manufactured 99.98% high purity Ta metal powder with 0.5 μm particle size. Thus, it was observed that adding the reducing reagent in excess favored the manufacture of high-purity Ta powder that can be applied in capacitors.
3
Content available remote Effects of different Sn contents on formation of Ti2SnC by self-propagating high-temperature synthesis method in Ti-Sn-C and Ti-Sn-C-TiC systems
Sun H Y, Kong X, Sen W, Yi Z Z, Wang B S, Liu G Y
Materials Science Poland
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2014
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Vol. 32, No. 4
696--701
EN
Effect of different Sn contents on combustion synthesis of Ti2SnC was studied using elemental Ti, Sn, C and TiC powders as raw materials in the Ti–Sn–C and Ti–Sn–C–TiC system, in which the molar ratio of Ti/C was set as 2:1. The reaction mechanism for the formation of Ti2SnC was also investigated. The results showed that the amount of Ti2SnC in combustion products firstly increased with increasing of Sn content (0.6 to 0.8 mol), and then decreased with further increasing of Sn content (1.0 to 1.2 mol). Upon addition of 15 % TiC instead of Ti and C, the optimum addition of Sn decreased to 0.7 mol and a higher purity of Ti2SnC was obtained. The Ti2SnC powders were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).
4
Nanokompozyty SiC/żywica epoksydowa : nowy materiał konstrukcyjny w przemyśle jachtowym
Dąbrowska A., Deuszkiewicz P., Huczko A.
Przegląd Mechaniczny
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2013
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nr 5
40--44
PL
Nanokompozyty, ze względu na ich szczególne właściwości i związane z tym potencjalne zastosowania, stanowią obecnie szczegółowo badaną grupę materiałów konstrukcyjnych. Popularne termoutwardzalne żywice epoksydowe mogą być stosowane jako matryce dla m.in. nanorurek węglowych i nanocząstek. W prezentowanej pracy wykorzystano nanowłókna węglika krzemu SiC (NWSiC) i ich wiązki (NWSiC*, tzw. nanogrzebienie) jako wypełniacz żywic epoksydowych. Dla obu wypełniaczy i żywic wykonane zostały serie próbek z zawartością nanowłókien/wiązek SiC od 0,1 do 3% wag. Pierwsze testy właściwości mechanicznych i dynamicznych potwierdziły wpływ zawartości dodatku już na poziomie 0,1 % wag. na właściwości żywicy. Wypełniacze wykorzystane do produkcji nanokompozytów zostały otrzymane metodą syntezy spaleniowej (SHS; Self-propagating High-Temperature Synthesis) z krzemu i teflonu i scharakteryzowane metodami fizykochemicznymi: SEM, TEM, XRD, spektroskopia Ramana.
EN
Nanocomposites are nowadays one of the most promising materials due to their outstanding mechanical, electrical and thermal properties that make them useful in various applications. The matrices of popular and available epoxy resins have been already blended with such fillers as carbon nanotubes and different kinds of nanoparticles. In this study, the SiC nanofibres (NFSiC) and their bundles (NFSiC*) were tested as a reinforcement of two epoxy resins. Several samples have been prepared in rangę from 0,1 up to 3% wt for both different types of resins and fillers. Preliminary mechanical and dynamical tests confirmed the change in polymer properties due to the incorporation of one-dimensional silicon Carbide (SiC). Fillers used in this study have been obtained by the Self-propagating HighTemperature Synthesis (SHS) from silicon and polytetrafluoroethylene powders and were characterized by SEM, TEM, XRD and Raman spectroscopy.
5
Content available remote Badania katalitycznych właściwości Ni3Al otrzymanego metodą wysokotemperaturowej samorozwijającej się syntezy
Kocemba I., Arkatova L., Rynkowski J. M.
Przemysł Chemiczny
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2011
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T. 90, nr 3
434-439
6
Content available remote The melt spreading along the substrate surface in the course of SHS surfacing
Yukhvid A. V., Stolin A. M., Yukhvid V. I., Stelmakh L. S.
International Journal of Applied Mechanics and Engineering
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2001
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Vol. 6, no 1
107-116
EN
The role of spreading during SHS surfacing of the protective coatings has been investigated theoreticaly and experimentally. The case, when spreading of large drops is forced by the effect of gravity and the interface forces are low, is considered. Analytical and numeric solutions of the problem have shown that the ratio of the specific times of cooling and spreading is the main parameter, which determines the dynamics and the final characteristics of spreading. It has been shown that the process of spreading is most strongly affected by the initial melt mass and drop size, the activation energy of viscosity, and gravitation (microgravitation and overload) within these specific times. The experimental research into SHS surfacing has confirmed the theoretical data.
7
Content available remote Materiały proszkowe i natryskiwane cieplnie powłoki zawierające fazy międzymetaliczne i tlenki z układu Fe-Ti-Al-O
Szymański K., Formanek B., Hetmańczyk M.
Problemy Eksploatacji
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2000
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nr 2
395-406
PL
W artykule przedstawiono kompleksową technologię wytwarzania nowych kompozytowych materiałów proszkowych typu 3A (alumina-aluminides-alloys) zawierających fazy międzymetaliczne z układów Fe-Al, Ti-Al i tlenek glinu przeznaczonych do natryskiwania cieplnego powłok o dużej żaroodporności i odporności na erozję w podwyższonej temperaturze. Do wytworzenia proszków zastosowano połączone procesy syntezy SHS i modyfikacji morfologii i składu chemicznego powierzchni proszków. Syntezą wysokotemperaturową mieszanin zawierających rudy tytanowe z aluminium otrzymano spieki, a następnie proszki zawierające aluminidki żelaza i tytanu umocnione dyspersyjnie tlenkiem glinu. Otrzymane w syntezie spieki były rozdrabniane w młynie rotacyjno-wibracyjnym, uzyskano proszki kompozytowe o określonym składzie fazowym i ziarnowym, które po procesie ich jakościowej kwalifikacji nadawały się bezpośrednio do natryskiwania cieplnego metodami płomieniowymi i plazmową. Określono procedurę technologiczną i parametry otrzymywania tych proszków. Określono strukturę oraz podstawowe i użytkowe własności (odporność na zużycie luźnym ścierniwem w temp. pokojowej i podwyższonej, stabilność temperaturową itd.) powłok otrzymanych w wyniku ich natryskiwania metodą naddźwiękową HVOF i plazmową.
EN
The paper presents the technological conception of obtaining composite powders of the type intermetallic phases - oxides in the system of iron and titanium aluminides and alumina. The scheme of technological procedure for preparation powders was presented. The phase composition of composite powders obtained by self-propagating high temperature, aluminothermal synthesis and also obtained by mechanicall alloying method was presented. The phase compositions, morphology, flowability, microstructure of powders are characterised. The microstructure, porosity and phase composition of coatings are characterised by light microscopy, quantitative analysis, and X-ray analysis. The wear resistance of coatings is characterised. The powders are used for manufacturing high temperature resistant coatings with good properties.
8
Content available remote Beta-sialon Ceramics Prepared Using Combustion Method
Lis J., Kata D.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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1999
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Vol. 47, nr 4
441-454
EN
The paper summarises the author's research on the preparation of dense beta-sialon materials using a combustion (SHS) method. The following aspects of sialon technology are discussed: the preparation of sialon powders, the powders characteristics, their processing and densification, as well as the characterisation of dense sialon polycrystals.
9
The microstructure of sialon materials produced by self propagating high temperature synthesis.
Kata D., Lis J.
Inżynieria Materiałowa
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1998
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R. XIX, nr 4
1258-1261
EN
The paper describes a preparation of dense sialon materials by using Self-Propagating High-Temperature Synthesis (SHS) followed by presureless sintering. The preparation route with an examination of final materials microstructure are discussed in details. The microstructures of the obtained sialons have shown dense, isotropic and fine-grain character without a presence of glass phase.
10
Manufacturing of Mo-Al intermetallics by SHS.
Mania R.
Inżynieria Materiałowa
|
1998
|
R. XIX, nr 4
921-924
EN
The self propagation high-temperature synthesis (SHS) was carried out in the equimolar powder mixture of molybdenum and aluminium. The reaction products Mo3Al8 and Mo3Al were analysed to determine chemical composition and microstructure. Density measurements using helium pycnometer permitted determination of molar fractions of molybdenum aluminides in the reaction product. Thus, the equimolar mixture of molybdenum and aluminium yielded about 23mol% Mo3Al8 and about 77mol% Mo3Al. The SHS products were densified by hot pressing (HP).
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