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PL
Zbadano termiczno-dynamiczne właściwości mechaniczne dwóch rodzajów kompozytów epoksydowych (na bazie żywicy Epidian 52 utwardzanej trietylenotetraaminą i żywicy Epidian 112 utwardzanej poliaminoamidem) modyfikowanych różną zawartością cząstek węgliku krzemu SiC i węgliku wolframu WC (10-56% każdej frakcji wagowej proszku w kompozycie). Ustalono wpływ składników na właściwości kompozytów. Przedstawiono typowe struktury SEM badanych próbek.
EN
Two types of epoxy resin-based composites filled with different contents of SiC and WC microparticles (10-56% of each powder mass fraction in the composite) were tested by dynamic-thermal analysis (DMA). The tests were performed using 2 bending modes. Based on the temp. characteristics of the DMA-tested materials, such as storage modulus, loss modulus and damping coeff., the glass transition temp. range was detd. Typical SEM structures of the studied samples were shown.
PL
Artykuł dotyczy problematyki komputerowego modelowania charakterystyk oraz parametrów tranzystorów MOS mocy wykonanych z węglika krzemu (SiC). W ramach realizacji pracy sformułowano oraz zaimplementowano w programie PSPICE autorski model rozważanego tranzystora, który bazuje na zmodyfikowanym modelu Shichmana-Hodgesa krzemowego tranzystora MOS. Opracowany model, w porównaniu do innych istniejących modeli tranzystora MOS wbudowanych w popularnych programach komputerowych, modeli firmowych, a także modeli opisanych w literaturze, cechuje się dużą dokładnością. Ponadto, zaproponowany model charakteryzuje się stosunkowo nieskomplikowaną budową, tzn. w zależnościach analitycznych opisujących ten model występuje zaledwie kilkanaście parametrów, których wartości można wyznaczyć korzystając z informacji zawartych w kartach katalogowych konkretnych typów tranzystorów albo na podstawie wyników pomiarów.
EN
The paper deals with the problem of computer modelling of characteristics and parameters of power MOSFETs made of silicon carbide (SiC). An original model of the considered transistor was formulated and implemented in the PSPICE program, which is based on the ShichmanHodges model of the silicon MOS transistor modified by the authors. In comparison to other existing MOS transistor models embedded in popular computer programs as well as models described in literature, the developed model exhibits high accuracy. Furthermore, the proposed model features a relatively simple structure, meaning that it includes only a few parameters in its analytical description. The values of these parameters can be determined based on the information provided in the datasheets of specific transistor types or through measurement results.
3
Content available remote Modelowanie diod SiCPiN w programie SPICE
PL
W pracy przeprowadzono ocenę możliwości wykorzystania programu SPICE do modelowania charakterystyk statycznych oraz czasowych przebiegów w zakresie przełączania diod PiN wykonanych w technologii węglika krzemu (SiCPiN). Przedmiotem badań są dostępne komercyjnie diody SiCPiN firmy GeneSiC. Wykazano, że wykorzystanie w symulacjach firmowych wartości parametrów występujących we wbudowanym w programie SPICE modelu diody prowadzą do istotnych różnic ilościowych, a nawet jakościowych pomiędzy kształtem charakterystyk rozważanych przyrządów półprzewodnikowych otrzymanych z obliczeń i pomiarów. Przeprowadzona przez autorów estymacja wartości tych parametrów doprowadziła do znacznej poprawy wyników symulacji
EN
In the paper, an assessment was carried out on the feasibility of using the SPICE program to model the static characteristics and switching waveforms of silicon carbide PiN diodes (SiCPiN). The focus of the research are commercially available SiCPiN diodes from GeneSiC. It was shown that using the parameter values provided by the built-in SPICE diode model could lead to significant quantitative and even qualitative differences in the shape of the characteristics of the considered semiconductor devices, compared to the results obtained from calculations and measurements. The authors conducted an estimation of these parameter values, leds to a significant improvement in the simulation results.
EN
The paper presents the results of a study on the microstructure and hardness measurements of Al4Cu-xSiC (x = 5, 10, 20 and 30 wt.%) composites produced by spark plasma sintering (SPS). The sintering process was carried out in an HP D 25/3 plasma sintering furnace in a vacuum atmosphere, with sintering temperatures of 580 and 600°C and a densification pressure of 50 MPa. The heating rate was 100°C/min and the isothermal holding time at the sintering temperature was 2.5 min. As a reference material, the AlCu matrix was sintered under the same conditions. As a result, composites with a near-full density of 96.5-99.5% were obtained. Microstructure studies were performed employing the techniques of light microscopy, scanning, and transmission electron microscopy, along with analysis of the chemical composition in microareas. The test results did not reveal remarkable differences in the microstructure of the investigated composites sintered at 580 and 600°C. The sinters have a fine-grained microstructure with a strengthening phase located at the grain boundaries; locally, pores are visible. Increasing the SiC content in the composites promotes the formation of agglomerates of these particles. It was proven that a higher sintering temperature has a positive effect on the hardness of the studied composites.
EN
In this research, aluminium metal matrix composites (AMMCs) have been manufactured through friction stir processing (FSP) by reinforcing nano-sized SiC particles in an Al6061-T6 alloy. The consequences of the volume percentage of reinforced SiC particles on mechanical properties and microstructural features were analyzed for the developed AMMCs. Microstructural evaluation of a cross-section of a friction stir processed (FSPed) sample has been conducted through Electron backscatter diffraction (EBSD) Energy dispersive spectroscopy (EDS) and a scanning electron microscope (SEM) technique. Microhardness tests were conducted athwart the cross section of FSPed specimen to obtain microhardness feature. A tensile test of FSPed samples has been conducted on a universal testing machine (UTM). Homogeneous distributions of SiC particles were found in the stir zone without any consolidation of particles. The size of the reinforcement particles was decreased slightly by increasing the volume fraction. It has been found that increasing the volume fraction of SiC particles, enhance the tensile strength and microhardness, but decreases the ductility of the aluminium. The maximum ultimate tensile strength (UTS) and microhardness were obtained as 390 MPa and 150.71 HV, respectively, at 12% volume percentage of reinforcement particles. UTS and microhardness of the FSPed Al/SiC have been improved by 38.29% and 59.48% respectively as compared to Al6061-T6. The brittle nature of the FSPed Al/SiC has increased due to a rise in the volume fraction of nanosized SiC particles, which causes a decrease in ductility.
PL
W artykule przedstawiono zagadnienia związane z inżynierią materiałową, ceramiką i odlewnictwem precyzyjnym. Opisano historię i przebieg procesu odlewania detali i części silników lotniczych metodą traconego wosku. Manuskrypt zawiera również generalne informacje o spoiwach, proszkach, masach formierskich, formach odlewniczych i nadstopach niklu. Zaprezentowano podstawowe dane o spoiwach zawierających nanocząstki ceramiczne, modelach woskowych, na które nanoszone są masy lejne oraz o SiC - jednym z perspektywicznych proszków formierskich.
EN
The paper presents the main issues related to materials engineering and technology, ceramics and precision casting process. The history and methodology of the lost-wax casting process of elements and aircraft engine parts is described. The manuscript also contains general information on binders, powders, molding compounds, foundry molds and nickel superalloys. Basic data on binders containing ceramic nanoparticles, wax models and SiC - one of the prospective molding powders are presented.
EN
The present investigation aimed to determine the optimal parameters for wire-cut electrical discharge machining (WEDM) for stir cast aluminum alloy AA6063 at 850°C reinforced with 10 wt.% green SiC (SiCg) and black SiC (SiCb) particles. The WEDM machining parameters, such as pulse on time (TON), wire feed (WF) rate, and flushing pressure (FP) of the resultant stir cast AA6063/SiCb and AA6063/SiCg composites, were optimized using the Taguchi method with L9 orthogonal array to estimate the responses, such as surface roughness and metal removal rate. Further, through grey relational analysis, the finest parameters for WEDM of AA6063/SiCb and AA6063/SiCg composites were evaluated as TON = 50 μs, WF rate = 18 m/min, and FP = 3 MPa. With the optimum parameters obtained, conformational experiments were conducted, and the scanning electron microscopic images were recorded, along with the energy-dispersive X-ray (EDX) spectroscopic data of the worn surfaces and debris. From the EDX mapping images of the machined surface, it was evident that AA6063/SiCb displays a more polished surface than AA6063/SiCg. However, for applications requiring a high metal removal rate, AA6063/SiCg displays better results than AA6063/SiCb.
EN
The article discusses benefits associated with the use of silicon carbide in the process of melting gray cast iron and ductile cast iron in induction electric furnaces. It presents the analysis of the impact of various charge materials and the addition of a variable amount of SiC and FeSi to the fixed charge when melting cast iron of grades GJS 400-15 and GJS 500-7 on mechanical properties and microstructure. Moreover, the article includes an analysis of the efficiency of carburization and the increase in the content of silicon during the application of SiC. The article also presents the results of the study of primary modification using silicon carbide at the minimum temperature of Temin eutectic and Tsol solidus. Based on analysis of the literature, conducted research, and calculations, it was found that the addition of silicon carbide has a beneficial impact on the properties of melted cast iron. The addition of SiC in the charge increases the content of C and Si without increasing the amount of contaminations. The addition of SiC at reduced pig iron presence in the charge decreases production costs, while the use of SiC as an inoculant increases both Temin and Tsol, which is beneficial from the point of view of cast iron nucleation.
9
Content available remote Reactive ion etching of 4H-SiC with BCl3 plasma
EN
The paper presents the results of plasma assisted reactive ion etching (RIE) of silicon carbide (4H-SiC). with a mixture of Ar and BCl3. The influence of input parameters such as process time, pressure, power and a ratio of working gases (Ar and BCl3) on the etch rate was investigated. The windows in SiO2 layer fabricated by PECVD process were patterned by photolithography. A stylus profilometry was a basic method of depth measurements after the etching processes.
PL
W pracy zaprezentowano wyniki reaktywnego trawienia jonowego (Reactive Ion Etching – RIE) węglika krzemu (4H-SiC) wspomaganego plazmą na bazie gazów roboczych Ar+BCl3. Przeprowadzono analizę wpływu parametrów procesu trawienia: czasu procesu, ciśnienia w komorze roboczej, mocy i stosunku gazów roboczych (Ar i BCl3) na głębokość i szybkość trawienia węglika krzemu. Jako maskę w procesach użyto osadzonego plazmowo SiO2, w którym zostały zdefiniowane okna przy pomocy fotolitografii. Pomiary głębokości po procesach trawienia zrealizowane zostały metodą profilometrii.
EN
Electrical properties of semiconductor materials depend on their defect structure. Point defects, impurities or admixture contained in a semiconductor material, strongly affect its properties and determine the performance parameters of devices made on its basis. The results of the currently used methods of examining the defect structure of semiconductor material are imprecise due to solution of ill-posed equations. These methods do not allow for determination of concentration of the defect centers examined. Improving the resolution of the obtained parameters of defect centers, determining their concentration and studying changes in the resistivity of semi-insulating materials can be carried out, among others, by modelling changes in the concentration of carriers in the conduction and valence bands. This method allows to determine how charge compensation in the material affects the changes in its resistivity. Calculations based on the Fermi-Dirac statistics can complement the experiment and serve as a prediction tool for identifying and characterizing defect centers. Using the material models (GaP, 4H-SiC) presented in the article, it is possible to calculate their resistivity for various concentrations of defect centers in the temperature range assumed by the experimenter. The models of semi-insulating materials presented in the article were built on the basis of results of testing parameters of defect centers with high-resolution photoinduced transient spectroscopy (HRPITS). The current research will allow the use of modelling to determine optimal parameters of semi-insulating semiconductor materials for use in photoconductive semiconductor switches (PCSS).
11
Content available TiAl-based Ohmic Contacts to p-type 4H-SiC
EN
This paper describes successfully formed ohmic contacts to p-type 4H-SiC based on titanium-aluminum alloys. Four different metallization structures were examined, varying in aluminum layer thickness (25, 50, 75, 100 nm) and with constant thickness of the titanium layer (50 nm). Structures were annealed within the temperature range of 800°C - 1100°C and then electrically characterized. The best electrical parameters and linear, ohmic character of contacts demonstrated structures with Al layer thickness equal or greater than that of Ti layer and annealed at temperatures of 1000°C or higher.
EN
The paper presents an investigation on the feasibility of recovery of the highly valuable silicon carbide (SiC) from the slurry waste generated from silicon wafer production in the photovoltaic and semiconductor industry. Compared to the other techniques of recycling, a facile and low-cost method of waste treatment via heat drying followed by low-energy mixing in a shaker mixer was proposed. As the result of the treatment, the slurry waste was converted into a powdered form with dominant content of SiC. Separated SiC material was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray powder diffraction, and sieve analysis. In addition, analyses of the bulk density, moisture content and melting test were carried out. As was confirmed by the physicochemical analyses, the dominant sieve fraction was in the range of 0.1-0.06 mm, the purity level was a minimum 99% mass of SiC, the moisture content - 0.3%, the bulk density - 1.3 g/cm3. The physicochemical characteristics of the material were crucial for understanding the material performance, assessment of the material quality and determining the perspective directions of the industrial application. The studies revealed that the material exhibited a high application potential as abrasive, especially in abrasive grinding and waterjet cutting.
EN
The main drawback of any Design for Reliability methodology is lack of easy accessible reliability models, prepared individually for each critical component. In this paper, a reliability model for SiC power MOSFET in SOT – 227 B housing, subjected to power cycling, is presented. Discussion covers preparation of Accelerated Lifetime Test required to develop such reliability model, analysis of semiconductor degradation progress, samples post-failure analysis and identification of reliability model parameters. Such model may be further used for failure prognostics or useful lifetime estimation of High Performance Power Supplies.
EN
This paper presents a concept of a shunt active power filter, which is able to provide more precise mapping of its input current drawn from a power line in a reference signal, as compared to a typical filter solution. It can be achieved by means of an interconnection of two separate power electronics converters making, as a whole, a controlled current source, which mainly determines the quality of the shunt active filter operation. One of these power devices, the “auxiliary converter”, corrects the total output current, being a sum of output currents of both converters, toward the reference signal. The rated output power of the auxiliary converter is much lower than the output power of the main one, while its frequency response is extended. Thanks to both these properties and the operation of the auxiliary converter in a continuous mode, pulse modulation components in the filter input current are minimized. Benefits of the filter are paid for by a relatively small increase in the complexity and cost of the system. The proposed solution can be especially attractive for devices with higher output power, where, due to dynamic power loss in power switches, a pulse modulation carrier frequency must be lowered, leading to the limitation of the “frequency response” of the converter. The concept of such a system was called the “hybrid converter topology”. In the first part of the paper, the rules of operation of the active filter based on this topology are presented. Also, the results of comparative studies of filter simulation models based on both typical, i.e. single converter, and hybrid converter topologies, are discussed.
15
Content available remote Przekształtniki tranzystorowe działające w trybie prądu trójkątnego
PL
Przekształtniki oparte na węgliku krzemu mogą być analizowane jako źródła napięcia lub prądu niezależnie od topologii przy odpowiednich parametrach filtru wyjściowego. Szczególnie interesujące są falowniki napięcia działające w trybie prądu trójkątnego. W referacie przedstawiono sterowanie trójfazowym falownikiem napięcia posiadającym właściwości źródła prądu. Pokazano, jak dobrać parametry filtru wyjściowego falownika. Oceniono sprawność systemów z falownikami działającymi w trybie prądu trójkątnego.
EN
Converters based on silicon carbide can be analysed as voltage or current sources, regardless of topology with appropriate parameters of the output filter. Voltage inverters operating in triangular mode are particularly interesting. The paper presents control of a three-phase voltage inverter having the properties of a current source. It was shown how to choose the parameters of the inverter output filter. The efficiency of systems with inverters operating in triangular current mode was assessed.
16
Content available remote Modelowanie charakterystyk Cj(u) tranzystora SiC-JFET
PL
W pracy omówiono problem modelowania wpływu wybranych czynników na właściwości tranzystora polowego wykonanego z węglika krzemu. Przeprowadzono badanie przydatności wbudowanego modelu tranzystora JFET w programie SPICE do analizy właściwości tego przyrządu półprzewodnikowego. Przedstawiono obliczenia zmodyfikowanym modelem tranzystora JFET z węglika krzemu, pokazujące poprawę dokładności modelowania. Ocenę dokładności zmodyfikowanego modelu przeprowadzono przez porównanie zmierzonych i obliczonych charakterystyk pojemnościowo-napięciowych.
EN
The paper discusses the problem of modelling the influence of selected factors on the properties of a field effect transistor made of silicon carbide. A study of the suitability of the built-in model of the JFET transistor in SPICE to analyze the properties of the semiconductor device. Calculations with a modified model silicon carbide JFET are presented. Showing an improvement in modelling accuracy. The accuracy of the modified model was performed by comparing the measured and calculated capacitive-voltage characteristics.
17
Content available remote Measurements of transient thermal impedance of SiC BJT
EN
The paper presents the computer-aided method of measuring of the transient thermal impedance of SiC BJTs. The advantages of this method are illustrated by means of measurements of the silicon carbide BJT operating at the different cooling conditions.
PL
W pracy przedstawiono komputerową metodę pomiaru przejściowej impedancji termicznej tranzystora SiC BJT. Zalety tego sposobu zilustrowano za pomocą pomiarów tranzystora SiC BJT pracującego w różnych warunkach chłodzenia.
PL
W pracy zaproponowano metodę przygotowywania topionych pereł do analizy chemicznej metodą XRF dla materiałów ogniotrwałych zawierających węglik krzemu. Opracowana metoda utleniania SiC zawartego w próbce za pomocą mieszaniny węglanu sodu i boraksu pozwala na uzyskanie stopu bez zniszczenia platynowych tygli. Z tak otrzymanego stopu przygotowuje się perły litowo-boranowe odpowiednie do analizy chemicznej metodą XRF. Poprawność uzyskiwanych wyników potwierdzono, wykonując analizy certyfikowanych materiałów odniesienia zawierających SiC.
EN
This paper proposes a method for the preparation of fused beads for chemical analysis using the XRF method for refractory materials containing silicon carbide. The developed method of oxidizing SiC contained in the sample with a mixture of sodium carbonate and borax allows to obtain an alloy without destroying the platinum crucibles. From the alloy thus obtained lithium-borate beads suitable for chemical analysis by XRF are prepared. The correctness of the obtained results was confirmed by the analysis of certified reference materials containing SiC.
19
Content available remote Płaski filtr ceramiczny – nowe rozwiązanie
PL
Przeprowadzono badania nad opracowaniem sposobu otrzymywania płaskiego filtra ceramicznego w postaci wielowarstwowej, dwustronnej membrany ceramicznej, charakteryzującego się tym, że jego wewnętrzną warstwę drenażową stanowi porowata, otwarta struktura, umożliwiająca uzyskanie wyższej wydajności filtracji z jednostki powierzchni filtracyjnej w porównaniu z rozwiązaniem obecnym na rynku. Na podstawie prób, wykonanych z wykorzystaniem znanych metod otrzymywania porowatych tworzyw z SiC, uzyskano prototypowy dysk filtracyjny. Przeprowadzone badania jego własności filtracyjnych potwierdziły, że w porównaniu z rozwiązaniem obecnym na rynku, umożliwia on uzyskanie wyższej wydajności filtracji z jednostki powierzchni oraz charakteryzuje się korzystniejszą zdolnością do regeneracji.
EN
Research has been carried out on developing a method for obtaining a flat ceramic filter in the form of a multilayer, double-sided ceramic membrane with an internal drainage layer with a porous, open structure. This structure allows higher filtration efficiency per filter surface unit compared to a solution available on the market. Based on the conducted trials, using the commonly applied methods of obtaining porous products from silicon carbide, a proto-type filtration disc was developed. Investigations into its filtration properties confirmed that compared to the solution currently available on the market, it enables obtaining a much higher filtration efficiency and is characterized by a better ability to regenerate.
EN
Four municipal waste incineration plants were visited in Belgium. Facilities mainly consist of grate furnaces. During stopping for maintenance, in situ observations were mainly realized in two plants, refractory and slag samples were collected. These samples were observed and analysed in laboratory: ICP chemical analysis, X-ray diffraction, scanning electron microscopy, EDS analysis, thermo-optical analysis. Three mechanisms of degradation were identified. Their appearance mainly depends on the location in the furnace. On site observation and laboratory investigations allow to understand and to model the degradation mechanisms of materials versus composition, temperature, and their locations in the furnaces.
PL
Odwiedzono cztery belgijskie spalarnie odpadów komunalnych. Obiekty składają się głównie z pieców rusztowych. Podczas postoju z powodu konserwacji w dwóch zakładach przeprowadzono głównie obserwacje in situ i pobrano próbki materiałów ogniotrwałych i żużla. Próbki te obserwowano i analizowano w laboratorium: analiza chemiczna ICP, dyfrakcja rentgenowska, skaningowa mikroskopia elektronowa, analiza EDS, analiza termooptyczna. Zidentyfikowano trzy mechanizmy degradacji. Ich występowanie zależy głównie od lokalizacji w piecu. Obserwacje na miejscu i badania laboratoryjne pozwalają zrozumieć i modelować mechanizmy degradacji materiałów w zależności od składu, temperatury i ich lokalizacji w piecach.
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