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1

SiN/SiO2 passivation stack of n-type silicon surface

El Amrani A., Si-Kaddour R., Maoudj M., Nasraoui C.

Materials Science Poland

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2019

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Vol. 37, No. 3

482--487

EN

The SiN/SiO2 stack is widely used to passivate the surface of n-type monocrystalline silicon solar cells. In this work, we have undertaken a study to compare the stack layer obtained with SiO2 grown by both rapid thermal and chemical ways to passivate n-type monocrystalline silicon surface. By varying the plateau time and the plateau temperature of the rapid thermal oxidation, we determined the parameters to grow 10 nm thick oxide. Two-step nitric acid oxidation was used to grow 2 nm thick silicon oxide. Silicon nitride films with three refractive indices were used to produce the SiN/SiO2 stack. Regarding this parameter, the minority carrier lifetime measured by means of QSSPC revealed that the refractive index of 1.9 ensured the best passivation quality of silicon wafer surface. We also found that stacks with nitric acid oxidation showed definitely the best passivation quality. In addition to produce the most efficient passivation, this technique has the lowest thermal budget.

2

Material balance of the technological process in the new foundry of new ferronikel in DRENAS 2017

Bajraktari-Gashi Zarife, Halilaj Behram

Journal of Technology and Exploitation in Mechanical Engineering

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2018

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Vol. 4, nr 1

29--35

EN

Experimental and industrial research of the technological process during the year 2017, including planning, is presented in this paper. That research was conducted in the new Foundry of new Ferronickel in Drenas, which is in the village of Cikatove, Drenas, the Republic of Kosovo. According to initial calculations, an amount of ore which would enter the process was determined, however the anticipated amount was different from the one used during the process. The same applies to fuel. Difference between the planned and the actual amount of ore used during the year 2017 resulted from the percentage of Ni in the amount of ore used in the foundry, demand for an Fe-Ni ferroalloy etc. The technological process in the foundry serves the purpose of processing ore of ironnickel with a high percentage of Ni in its composition. The material balance of the technological process in the new Foundry of new Ferronickel in Drenas, presented in this paper, is based on experimental and industrial data of the technological process acquired in the foundry. The material balance includes the technological process starting from calculation of the amount of ore and fuel, both making up the load for the rotary kiln. Additional contributors to the material balance are calculation of the amount of: fuel, which impacts the increase of temperature in rotary kilns, charge for the electric furnaces, metal and slags from the electric furnaces, metal and slags from the refining process (convertors) and mathematical calculation of the final product which is the ferroalloy of Fe-Ni. While preparing the material balance we have noticed greater acquisition of Ni than planned. The greater amount of Ni was produced by a smaller amount of ore than originally planned.

3

Modification of graphene oxide and reduced graphene oxide with inorganic nanoparticles

Jagiełło J., Baran M., Lipińska L.

Engineering of Biomaterials

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2018

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Vol. 21, no. 148

50

4

Applications of flake graphene in tissue engineering

Lipińska L., Jagiełło J., Baran M., Kurp K.

Engineering of Biomaterials

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2018

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Vol. 21, no. 148

51

5

Modeling of Precipitate Oxide and Sulfide Inclusions Formation in Liquid Steel

Didenchuk D., Kalisz D.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 4 spec.

19--22

EN

The behaviour of non-metallic inclusions MnO, MnS, FeS, Al2O3, SiO2, Y2O3,Y2S3 in liquid steel were modelled in commercial software FactSage. It allowed for calculating and designing diagrams of dependence of inclusions formation from the concentration of yttrium in determined limits of aluminium and oxygen. As a result, the influence of the increasing yttrium concentration on the precipitations of oxide and sulfide inclusions is observed. The behavior of precipitation the another analyzed oxides and sulfides is also observed in liquid steel, giving a full composition in non-metallic inclusions, formatted in specified conditions. The amounts of mass fractions of Y2O3 and Y2S3 are increasing at the growing Y in liquid steel, which shows the active formation of these inclusions.

6

Structural elastic and thermal properties of Sr x Cd1−x O mixed compounds — a theoretical approach

Bhardwaj P.

Materials Science Poland

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2014

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Vol. 32, No. 3

350--357

EN

In the present paper, the structural and mechanical properties of alkaline earth oxides mixed compound SrxCd1-xO (0 6 x 6 1) under high pressure have been reported. An extended interaction potential (EIP) model, including the zero point vibrational energy effect, has been developed for this study. Phase transition pressures are associated with a sudden collapse in volume. Phase transition pressure and associated volume collapses [DV (Pt)/V(0)] calculated from this approach are in good agreement with the experimental values for the parent compounds (x = 0 and x = 1). The results for the mixed crystal counterparts are also in fair agreement with experimental data generated from the application of Vegard’s law to the data for the parent compounds.

7

Formation of silicon oxide nanowires in nanomaterial synthesis experiments based on the usage of tube furnace

Li C., Solomon V., Moro M., Welsh C., Mccauley T., Bauer M., Cupo J.

Materials Science Poland

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2013

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Vol. 31, No. 3

350--356

EN

In an effort to synthesize doped ZnO nanowires, SiOx nanowires were obtained accidently. In the experiment, mixed powders containing chemicals such as ZnO, graphite, Ga2O3, and In2O3 were placed in the center of a tube furnace, where the temperature was set to 1200 °C and the vacuum was approximately 27 Pa. Silicon wafers were placed around the vicinity of the furnace exit to collect the expected nanomaterials. After prolonged heating, grey layers were found on top of one wafer located inside the furnace. The layer showed no adhesion to the substrate. Characterization by using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Energy Dispersive X-ray Spectroscopy (EDS) revealed that this layer consisted of SiOx nanowires. Formation of Si-containing liquid drop and the subsequent growth of SiOx nanowires out of it are suggested as the growth mechanism.

8

Strength and tribological properties of sintered powder composite materials based on copper with addition of alumina and nickel oxide

Feldshtein E., Dyachkova L.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 1

41-52

EN

In the paper, the influence of oxide addition on the strength and mechanical properties of a sintered powder material based on copper is described. The increase of alumina content in the composite sintered material leads to decreasing its strength. The most significant decrease of strength is observed when less than 5% of alumina is added to the total volume. A further increase of the alumina content practically leaves the bending strength unchanged and decreases the strength limit in compression insignificantly. The addition of mixture of 80% of the alumina and 20% of the nickel oxide increases the bending strength about 40 50 MPa, and also promotes the formation of a more homogeneous and fine-grained structure, as well as decreases material porosity. The average coefficient of friction of the "sintered composite material - hardened steel C45" pair practically did not change over time. The lowest coefficients of friction were observed for a material containing alumina addition. An addition of Motor Life Professional additive to the lubricant oil reduces the coefficient of friction for the material free of oxides more than 30%. The temperature of friction is reduced by 25÷30% and the rate of linear wear decreases 1.4 to 3 times.

9

Interactions at the mould - modifying coating - molten nickel alloy interface

Binczyk F., Śleziona J., Gradoń P., Michalska J., Bąk S.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3

5-10

EN

The study describes thermal-chemical interactions that take place in the molten nickel alloy-ceramic mould system, where the mould is either coated with a modifying coating ('blue' mould) or is not ('white' mould). The ceramic mould based on zirconium silicate was made by investment process at the WSK Rzeszów Foundry. The main component of the modifying coating was cobalt aluminate CoAl2O4 added in an amount of 10%. Thermodynamic calculations indicated the possibility of chemical reactions taking place between the chemically active nickel alloy constituents (Al, Ti, Hf, Ta and Nb) and the components of a ceramic mould and modifying coating. The result of such interactions is the risk of the formation of cracks on the surface of mould and molten metal penetration into these cracks, combined with the formation of casting defects, like burns-on, pitting, etc., as proved by extensive X-ray microanalysis. Changes of chemical composition in the surface layer of castings were also reported.

10

Comparison of surface laser alloying of chosen tool steel using Al2O3 and ZrO2 powder

Labisz K., Dobrzański L. A., Jonda E., Lelątko J.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 1

87-94

EN

Purpose: In this work there are presented the investigation results of mechanical properties and microstructure of the hot work tool steel 32CrMoV12-28 alloyed with oxide powders like aluminium oxide and zirconium oxide. The purpose of this work was also to determine the laser treatment conditions for surface hardening of the investigation alloys with appliance of transmission electron microscopy. Design/methodology/approach: The investigations were performed using optical microscopy for the microstructure determination. By mind of the transmission electron microscopy the high resolution and phase determination was possible to obtain. The morphology of the ceramic powder particles was studied as well the lattice parameters for the Fe matrix and phase identification using diffraction methods was applied. Findings: After the laser alloying of the hot work tool steel with the selected oxide powders the structure of the samples changes in a way, that there are zones detected like the remelting zone the heat influence zone where the grains are larger and not so uniform as in the metal matrix. The used oxide powders are not present after the laser treatment in the steel matrix. Research limitations/implications: The investigated steel samples were examined metallographically using optical microscope with different image techniques, SEM, TEM and analyzed using a Rockwell hardness tester, also EDS microanalysis and electron diffraction with Fourier transform was made. Practical implications: As an implication for the practice a new technology can be possible to develop, based no diode laser usage. Some other investigation should be performed in the future, but the knowledge found in this research shows an interesting investigation direction. Originality/value: The combination of TEM investigation for laser alloying of hot work tool steels makes the investigation very attractive for automotive and other heavy industries.

11

Tb₃Sc₂Al₃O₁₂-TbScO₃ eutectic self-organized microstructure for metamaterials and photonic crystals application

Kołodziejak K., Turczyński S., Diduszko R., Klimek L., Pawlak D. A.

Opto-Electronics Review

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2006

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Vol. 14, No. 3

205-211

EN

Eutectics are the materials with foreseen application in the field of photonic crystals and metamaterials. In this paper, the dependence on chemical composition of the microstructures of terbium-scandium-aluminium garnet and terbium-scandium perovskite (Tb₃Sc₂Al₃O₁₂-TbScO₃) eutectics has been studied. The growth of the eutectic rods by the micro-pulling down method is presented, using compositions with several different volume fractions of the garnet and the perovskite phases, VTSAG:VTSP = 4, 3, 2, 1, 1/2. The phases have been characterized by powder X-ray diffraction and energy dispersive spectrometry. The relationship between the lattice constant of individual phases and the chemical composition is presented. The unidirectional growth of microrods has been also investigated by electron backscattering diffraction.

12

Evaluation of points of zero charge of aluminum oxide reported in the literature.

Kosmulski M.

Prace Naukowe Instytutu Górnictwa Politechniki Wrocławskiej. Konferencje

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2001

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Vol. 95, nr 31

5-14

EN

In 1965 Parks compiled PZC of metal oxides and hydroxides and his paper is still the most frequently cited source of PZC of these materials. The recent compilation (Kosmulski 2001) covers not only oxides and hydroxides, but also mixed oxides, sparingly soluble salts and other materials whose surface charging is pH dependent. One set of data from this compilation (155 PZC of AL2O3 published in 150 papers between 1969 and 2001) was selected to show the effect of crystalline structure on the one hand and of the choice of the experimental method on the other on the PZC. There is no significant difference between the ? form (32 entries, average 8.2, median 8.55) and the ? form (58 entries, average 8.2, median 8.4) and the other forms, mixtures of different forms and materials of unknown structure (65 entries, average 8.3, median 8.7). On the other hand, the choice of the method substantially affects the PZC. The isoelectric point IEP from electroacoustic measurements (11 entries, average 9.3, median 9.5) is significantly above the IEP from classical electrokinetic measurements (78 entries, average 8.2, median 8.7) and potentiometic titration at one ionic strength (29 entries, average and median 8). The results obtained by means of two latter methods are much more scattered than in other methods. The lowest standard deviation was observed in the set of PZC obtained by means of combination of titration (the common intersection point of titration curves for three or more ionic strengths is identified with the PZC) and electrokinetic measurements (7 entries, average and median 8.6), and this value is the "recommended" PZC for alumina.

PL

Parks opublikował w 1965 roku przegląd PZC tlenków I wodorotlenków metali, który do chwili obecnej jest najczęściej cytowanym źródłem informacji. Najnowszy przegląd PZC (Kosmulski 2001) obejmuje nie tylko tlenki i wodorotlenki metali, lecz również tlenki mieszane, trudno rozpuszczalne sole i inne materiały, których ładunek powierzchniowy zależy od pH. Na podstawie przykładowego zestawu danych z tego przeglądu (155 wartości PZC dla Al2O3 opublikowano w 150 pracach w latach 1969-2001) badano wpływ struktury krystalograficznej próbki i doboru metod doświadczalnych na otrzymaną wartość PZC. Stwierdzono brak istotnej różnicy pomiędzy odmianami. Alfa (32 wartości, średnia 8.2, mediana 8.55) i (58 wartości, średnia 8.2, mediana 8.4) oraz innymi odmianami, mieszaninami różnych odmian i materiałami o nieznanej strukturze (65 wartości, średnia 8.3, mediana 8.7). natomiast wartości PZC wyraźnie zależą od zastosowanej metody. Metoda elektroakustyczna (1l wartości, średnia 9.3, mediana 9.5) daje zdecydowanie wyższy punkt izoelektryczny IEP niż klasyczne metody elektrokinetyczne (78 wartości, średnia 8.2, mediana 8.7) i miareczkowanie potencjometryczne przy jednej sile jonowej (29 wartości, średnia i mediana 8). W dwóch ostatnich metodach odchylenie standardowe jest większe niż w pozostałych metodach. Najmniejsze odchylenie standardowe występuje w zbiorze danych otrzymanych przy jednoczesnym zastosowaniu miareczkowania potencjometrycznego (jako PZC przyjmuje się punkt przecięcia krzywych miareczkowania przy co najmniej trzech rożnych siłach jonowych) i pomiarów elektrokinetycznych (7 wartości, średnia i mediana 8.6) i tę wartość można uznać za najbardziej wiarygodną.

13

Rozkład termiczny benzo[a]pirenu w obecności y-Al2O3

Szopa M., Szustakowski M.

Chemia i Inżynieria Ekologiczna

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2000

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Vol. 7, nr 7

773-779

PL

Prowadzono badania modelowe nad degradacją benzo(a)pirenu (BaP) w obecności y-Al2O3 w zakresie temperatury 423-573 K, przy dwóch różnych obciążeniach objętościowych reaktora. Obserwowano spadek stężenia BaP w produktach ze wzrostem temperatury procesu oraz obniżeniem obciążenia objętościowego reaktora. Przy założeniu, że reakcja degradacji BaP w niskich temperaturach przebiega wg mechanizmu reakcji II rzędu, obliczono stałe szybkości reakcji degradacji BaP. Energię aktywacji reakcji degradacji BaP oszacowano na 10,7 kl/mot

EN

Decomposition of benzo[a]pyrene (BaP) at the temperature range of 423-573 K in presence of y-Al2O3 was examined in model conditions at two various loads of the reactor. Both the reference sample and the BaP decomposition products were analyzed with a capilIary column gas chromatograph. Increase in temperature of the process and reduction of the load were accompanied by reduction of BaP concentration in the products. Assuming that at low temperature decomposition of BaP follows the second order reaction kinetics, the rate constants were computed. It was estimated that the activation energy of the BaP decomposition process amounts to 10.7 kJ/mol.

14

Termodynamiczne i kinetyczne uwarunkowania reakcji chemicznych na powierzchni żelaza i chromu w atmosferze SO2 w wysokiej temperaturze.

Gilewicz-Wolter J., Żurek Z., Środa S.

Inżynieria Materiałowa

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1999

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R. XX, nr 5

558-561

PL

W pracy przedyskutowano termodynamiczne i kinetyczne uwarunkowania tworzenia się zgorzelin tlenkowo-siarczkowych na żelazie i chromie w atmosferze SO2. Proces korozji żelaza i chromu jest bardzo złożony i można go wyjaśnić tylko w oparciu o przesłanki kinetyczne jak i termodynamiczne. Transport reagentów przez rosnącą zgorzelinę jest czynnikiem decydującym o przebiegu procesu korozji i budowie morfologicznej zgorzeliny.

EN

The oxidation of Fe and Cr in SO2 has been studied at 1073K-1273K at 100K intervals. The corrosion kinetics follows the parabolic rate law to a good approximation for iron. Only small deviation from parabolic rate law in initially stage process was observed, whereas oxidation process of chromium proceeds according linear rate law at 10 to the 5 Pa of SO2, parabolic rate law at 1173K and 1273 at 3*10 to the 4 Pa of SO2. The transport phenomena by radiotracer techniques were studied. The scales were composed of sulphide and oxide and grew by the outward diffusion of metals. Inward transport of SO2 molecules through the discontinuities in the scale was observed. The mechanism of sulphide and oxide formation was discussed on the basis of the thermodynamics and kinetics predictions.

15

Composite aluminide - oxide phase powders for thermal spraying processes.

Formanek B., Hetmańczyk M., Szymański K.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1019-1022

EN

Article presents technological conception of composite powders manufacturing by the SHS method in the system of iron and titanium aluminides and aluminium and titanium oxides. High temperature synthesis parameters and the phase composition of powders were determined. The obtained powders are used for forming thermal barrier coatings.

16

Aqueous processing of SiAlON powders.

Kudyba A., Serkowski S., Hintzen H.T., Metselaar R.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1268-1271

EN

To manipulate and understand the suspension behaviour in water of carbothermally prepared Ca-alpha-SiAlON and beta-SiAlON powders, to be processed by slip casting, different characterization methods were applied. These concerned: zeta potential, ESA, rheological sedimentation and floc size measurements. The best deflocculation was found at pH 10-11 where both investigated powders showed the lowest viscosity (below 10 MPa's), the lowest sediment volumes and the highest absolute of zeta potentials. At this pH the suspensions where considered to have the most favourable condition for this chosen process. The powders showed similar suspension behaviour (viscosity, behaviour, sedimentation behaviour, isoelectric points) suggesting similar surface characteristics probably due to resemblance of the surface due to oxidation treatment after carbothermal synthesis. Rheometry and zeta potential were found to be fast techniques providing the most useful and complete information of slip behaviour allowing a good choice of suspension parameters.