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1

Analysis of the Chemical Compositions of Locally Branded Manufactured Cement of Pakistan

Sultan Muhammad Adil, Jawad Muhammad, Din Salah Ud, Cheema Shahan M., Mushtaq Aamir

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 3

147--152

EN

Cement is a key component of concrete; its qualities impact the properties of concrete created using a particular type of cement. In Pakistan, cement brands are used for an enormous amount. As a result, the cement qualities must fulfill the standards defined by the rules. This research compares the chemical properties of Paidaar, Lucky, DG, Fauji, and Bestway cement brands. This research compares the chemical properties of Paidaar, Lucky, DG, Fauji, and Bestway cement brands. The chemical analysis of cement was used to compute the compound composition of C3S, C2S, C3A, and C4AF. It was discovered that the Al2O3 and SO3 levels in Paidaar and Fauji cement exceeded the specified limits. The presence of more SO3 causes sulphates in cement to expand. Furthermore, a study of four key components (C3S, C2S, C3A, and C4AF) revealed that Paidaar, Lucky, and Fauji cement have less C3S and more C2S, as a result, when compared to other cement brands, it has the lowest strength. When different brands’ chemical compositions were compared, the Paidaar, Lucky, DG, Fauji, and Bestway cements fulfilled the standards’ recommended ranges. To ensure the quality specified by the standards, Paidaar, Lucky, and Fauji cement require significant quality control during the manufacturing process.

2

Thermal stability of nanoscale oxides and carbides of W and Zr in Cu-Al-Fe alloy

Zatulovskyi A.S., Shcheretskyi V.O., Shcheretskyi A.O.

Journal of Achievements in Materials and Manufacturing Engineering

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2018

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Vol. 90, nr 2

49--57

EN

Purpose: of this paper is to discover phases evolution of nanoscale tungsten, zirconium oxides and carbides during heating up to 1200°C in contact with the copper alloy CuAl8Fe3. Design/methodology/approach: The main investigation methods are X-ray phase analysis and thermal analysis. The X-ray phase analysis is done by automated X-ray diffractometer DRON-3.0 with cobalt anode, the thermal analysis is done with synchronous thermal analyser STA 449F1 Jupiter (NETZSCH). Findings: The initial interactions’ temperatures for the carbides and oxides with copper alloy CuAl8Fe3, also temperatures of isomorphic and polymorphic transitions are discovered. Comparative thermal analysis of the nanoscale powders reveals carbides are more stable in air and inert gas (argon) versus oxides ones. Research limitations/implications: Intermediate phase transitions during heating and cooling are predicted on the base of known thermodynamic data and scientific reports, X-ray phase analysis is performed only for initial and result material before and after heat treatment. Practical implications: Obtained data allows developing effective technological consolidation regimes of ESD nanoscale zirconium, tungsten carbides and oxides with cuprum-based alloys for wear and heat resistant composite materials production. Originality/value: The paper exposes new thermal data of isomorphic and polymorphic transformations for zirconium, tungsten carbides and oxides nanoscale powders obtained by ESD and their interactions with copper CuAl8Fe3 alloy in temperature range: 25-1200°C.

3

Characterization of NiO–Al2O3 composite and its conductivity in biogas for solid oxide fuel cell

Patil S. P., Jadhav L. D., Dubal D. P., Puri V. R.

Materials Science Poland

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2016

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Vol. 34, No. 2

266--274

EN

NiO–Al2O3 nanocomposite has been synthesized by mixing combustion synthesized powders. The nanocomposite is an effective anode/anode functional layer for intermediate temperature solid oxide fuel cells. The TEM of NiO and Al2O3 revealed spherical particles of 30 nm and platelets of 70 nm, respectively. The XRD analysis of NiO– Al2O3 composite sintered at 900 °C showed presence of cubic NiO and rhombohedral α- Al2O3 which were chemically stable. However, above 1200 °C Ni Al2O4 started to appear. The conductivity of NiO– Al2O3 was the highest in hydrogen (4.3 × 10–3 S/cm at 600 °C). In biogas, the conductivity was 3.2 × 10–3S/cm with the activation energy of 0.67 eV. The stability of the composite in biogas was also examined.

4

Green synthesis and characterization of Ag1/2Al1/2TiO3 nanoceramics

Kumar S., Jha A. K., Prasad K.

Materials Science Poland

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2015

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Vol. 33, No. 1

59--72

EN

Single phase silver aluminum titanate (Ag1/2Al1/2)TiO3, later called AAT, nanoceramic powder (particle size 2 to 7.5 nm) was synthesized by a low-cost, green and reproducible tartaric acid gel process. X-ray, FT-IR, energy dispersive X-ray and high resolution transmission electron microscopy analyses were performed to ascertain the formation of AAT nanoceramics. X-ray diffraction data analysis indicated the formation of monoclinic structure having the space group P2/m(10). UV-Vis study revealed the surface plasmon resonance at 296 nm. Dielectric study revealed that AAT nanoceramics could be a suitable candidate for capacitor applications and meets the specifications for “Z7R” of Class I dielectrics of Electronic Industries Association. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. To find a correlation between the response of the real system and idealized model circuit composed of discrete electrical components, the model fittings were performed using the impedance data. Electric modulus studies supported the hopping type of conduction in AAT. The correlated barrier hopping model was employed to successfully explain the mechanism of charge transport in AAT. The ac conductivity data were used to evaluate the density of states at Fermi level and minimum hopping length of the compound.

5

Wpływ dodatku tlenku cynku na właściwości mikrostrukturalne surowych szkliw ceramicznych

Leśniak M., Sitarz M., Partyka J., Gasek K.

Materiały Ceramiczne

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2014

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T. 66, nr 4

408--411

PL

W niniejszej pracy zbadano wpływ tlenku cynku (ZnO) na właściwości mikrostrukturalne surowych szkliw ceramicznych z układu SiO2-Al2O3-MgO-CaO-K2O-Na2O. Mikrostrukturę badano metodą skaningowej mikroskopii elektronowej (SEM) z analizatorem składu pierwiastkowego w mikroobszarach (EDS), dyfrakcją promieniowania rentgenowskiego (XRD) oraz spektroskopią w podczerwieni (FTIR). Dyfrakcja rentgenowska oraz badania w zakresie środkowej (MIR) i dalekiej (FIR) podczerwieni wykazały, że tlenku cynku dodany w ilości 6% wagowych pełni funkcję modyfikatora struktury szkliw.

EN

In the present study the influence of zinc oxide (ZnO) on microstructural properties of row ceramic glazes from the SiO2-Al2O3-MgO-CaO-K2O-Na2O system were examined. The microstructure of glazes were determined by scanning electron microscopy (SEM) with an elemental composition analyzer in microareas (EDS), X-ray diffraction (XRD) and infrared spectroscopy (FTIR). X-ray diffraction, mid-infrared spectroscopy (MIR) and far-infrared spectroscopy (FIR) showed that zinc oxide incorporated to the glazes in an amount of 6% weight was a modifier of the glaze structure.

6

Magnetic properties of manganese doped PrAlO3 monocrystalline fibres

Guzik A., Talik E, Pajączkowska A, Turczyński S, Kusz J

Materials Science Poland

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2014

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Vol. 32, No. 4

633--640

EN

Monocrystalline fibres of undoped PrAlO3 and PrAlO3:0.1 Mn, have been grown by the pulling-down method under nitrogen atmosphere. The as-grown crystal doped with Mn had a visible brown core surrounded by a green ring, whereas this effect was weaker for the undoped PrAlO3. A coloration of the brown core was caused by a presence of Pr4+ ions. The presence of the Pr4+ ions was confirmed by XPS and magnetic studies. The XPS chemical analysis showed the increased concentration of oxygen in the crystals with the brown core. The most probable valency of manganese is Mn4+. It is located in Al3+ sites.

7

Wpływ stężenia napełniacza w smarze plastycznym na efektywność smarowania stalowych węzłów ślizgowych pracujących przy tarciu mieszanym

Krawiec M., Czupryk W.

Tribologia

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2012

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nr 4

99-106

PL

W publikacji przedstawiono wyniki badań rozpoznawczych nad wpływem różnych napełniaczy (Bi₂O₃, Sb₂O₃, CuO, ZnO, TiO₂) w wapniowym smarze plastycznym (Maszynowy 2) na efektywność smarowania stalowych skojarzeń ślizgowych. Badania tribologiczne przeprowadzono na aparacie czterokulowym. Analizie poddano kompozycje smarowe mające 4 i 10% wagowo każdego z przyjętych napełniaczy. Dla celów porównawczych wyznaczono charakterystyki tribologiczne Smaru Maszynowego 2 bez napełniacza. Efektywność analizowanych smarów oceniono według dwóch wielkości kryterialnych, tj.: granicznego obciążenia zatarcia Foz oraz granicznego nacisku zatarcia poz. Wyniki eksperymentu opracowano statystycznie na poziomie ufności 95%, stosując test t-Studenta. Stwierdzono, że dwutlenek tytanu, tlenek cynku i trójtlenek bizmutu są mało efektywnymi napełniaczami Smaru Maszynowego 2. Ponadto zaobserwowano, że zmiana stężenia tlenku miedzi lub trójtlenku antymonu z 4% do 10% powoduje zwiększenie efektywności smarowania.

EN

The paper presents the results of preliminary studies into the effect of different fillers (Bi₂O₃, Sb₂O₃, CuO, ZnO, TiO₂) in calcium grease (Machine Grease 2) on the efficiency of the lubrication of steel sliding pairs. Tribological tests were carried out using a four-ball tester. Grease mixtures containing 4% and 10% by wt. of one of the fillers were tested. For purposes of comparison, the tribological characteristics of Machine 2 grease without any filler were determined. The efficiency of the greases was evaluated according to two criteria: limit seizure load Foz and limit seizure pressure poz. The experimental results were statistically processed at a confidence level of 95% using Student's t-test. Titanium dioxide, zinc oxide, and bismuth trioxide were found to be poorly effective fillers of Machine Grease 2. Moreover, it was found that a change in the concentration of copper oxide or antimony trioxide from 4% to 10% results in an increase in lubrication efficiency.

8

Conduction in nanostructured La1=x Sr x FeO3 (0 <= x <= 1)

Zafar A., Imran Z., Rafiq M. A., Shah S. H., Hasan M. M.

Materials Science Poland

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2012

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Vol. 30, No. 3

240--247

EN

We investigated electrical properties of nanostructured La1?x Sr x FeO3 (0 <= x <= 1) from 300 K-400 K. The nanostructured La1-x Sr x FeO3 (0 <= x <= 1) was synthesized by citrate gel method requiring no pH control. X-ray diffraction pattern showed that single phase LaFeO3 with an orthorhombic structure was formed. The structure changed into rhombohedral for x = 0.5 and it became cubic for x = 1.0. For x <= 0.5, our material showed non-linear current-voltage characteristics and for x > 0.5 it showed linear current-voltage characteristics. Poole Frenkel type conduction mechanism was found to be operative in LaFeO3 from 300 K-400 K. The experimental values of field-lowering coefficient were by 2.56-6.41 times higher than the predicted value and were attributed to the presence of localized fields. The increase in conductance with Sr content was due to formation of Fe4+ ions in addition to Fe3+ with the increase in Sr content. Impedance spectroscopy and ac conductivity analysis of La1-x Sr x FeO3 (0 <= x <= 1) was also carried out in the temperature range from 300 K-400 K and frequency was varied from 20 Hz - 2 MHz. The ac conduction followed the correlated barrier hopping model in La0.9Sr0.1FeO3.

9

Wpływ procesów rozwijania powierzchni miedzi na wielkość zmian rezystancji rezystora cienkowarstwowego formowanego z folii NiP

Lipiec K., Araźna A., Borecki J., Futera K.

Elektronika : konstrukcje, technologie, zastosowania

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2011

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Vol. 52, nr 7

88-90

PL

Dbałość o środowisko naturalne zakłada zmniejszenie ilości wytwarzanych odpadów i wymusza konieczność wprowadzania nowych rozwiązań, które pozwolą zmniejszyć powierzchnię płytki drukowanej. Jednym z takich rozwiązań jest formowanie rezystorów cienkowarstwowych z folii NiP. Uformowane rezystory na warstwach wewnętrznych uwalniają więcej miejsca na inne podzespoły elektroniczne montowane na warstwie zewnętrznej płytki drukowanej. Aby dowiedzieć się, jak na rezystancję rezystora wpływają procesy rozwijania powierzchni miedzi wykonano szereg badań.

EN

Taking care of natural environment assumes reduction in the amount of manufacturing wastes. Therefore, it is necessary to introduce new solutions which will allow for reduction of printing plate surface. One of such solutions is formation of thin - layered resistors from NiP foil. Formed resistors on internal layers discharge morę space for other electronic subcomponents assembled on external layer of the printing plate. To learn how the resistance of the resistor affects the processes of developing a copper surface some research was carried out.

10

Simulation of oxygen and nitrogen removal from steel by means of titanium and aluminum

Iwanciw J., Podorska D., Wypartowicz J.

Archives of Metallurgy and Materials

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2011

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Vol. 56, iss. 3

635-644

EN

Authors' computer program was employed in the simulation of the course of steel refining by means of simultaneously used aluminium and titanium. The mass and chemical composition of liquid steel and non-metallic precipitates, were calculated at constant or variable temperature. The influence of assumed nitrides form on the results of simulation was determined. Nitrides may be considered either as separate phases or as the components of non-metallic solution. The stoichiometry of titanium oxide obtained also influences the results of simulation. Parallel analysis of steel refining was carried out with the use of FactSage program. As a result of calculations the subsequent states of equilibrium between steel and non-metallic phase were determined. It was found that aluminium and titanium nitrides may exist only as the components of oxide-nitride solution, not as separate phases.

PL

Przy pomocy własnego programu komputerowego dokonano symulacji przebiegu rafinacji stali przy pomocy glinu i tytanu, wyznaczając masę i skład chemiczny ciekłej stali i wydzieleń niemetalicznych dla ustalonej lub zmiennej temperatury. Rozpatrzono konsekwencje występowania dwóch możliwych form istnienia azotków glinu i tytanu: jako odrębnych faz i jako składników ciekłego roztworu. Również stechiometria tlenku tytanu uzyskanego w wyniku odtleniania wpływa na wynik obliczeń. Równoległą analizę tego samego przypadku przeprowadzono przy pomocy programu FactSage, wyznaczając kolejne stany równowagi między ciekłą stalą a fazą niemetaliczną. Stwierdzono, że azotki glinu i tytanu mogą występować tylko jako składniki roztworu tlenkowo-azotkowego., nie zaś jako odrębna faza.

11

Preparation of magnesium oxide (MgO) from dolomite by leach-precipitation-pyrohydrolysis process

Yildirim M., Akarsu H.

Physicochemical Problems of Mineral Processing

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2010

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Vol. 44

257-272

EN

Magnesium oxide suitable for the use in basic refractories was prepared from dolomite (CaMg(CO3)2) by hydrochloric acid leaching, precipitation with CO2 and thermal hydrolysis. Leaching of the dolomite ore in aqueous hydrochloric acid solution was investigated with respect to the effects of time on dissolution of the dolomite sample. The dependence of the observed dissolution rate on pH was established. In the carbonation experiments changes in pH, Ca2+ and Mg2+ concentrations versus time in the effluent solution were determined. Effects of the temperature on the precipitation rate of Ca2+ ions as solid CaCO3 were studied. Experiments were conducted to determine the kinetics of thermal decomposition of MgCl2.6H2O during pyrohydrolysis process. From high purity magnesium chloride brine magnesium oxide containing 98.86 % MgO was obtained with the thermal decomposition recovery of 98.10 %.

PL

Z dolomitu otrzymano tlenek magnezu przydatny do produkcji zasadowych materiałów ognioodpornych. Otrzymano go za pomocą ługowania kwasem solnym i wytrącania z użyciem CO2 oraz stosując termiczną hydrolizę. Badano ługowanie dolomitu w roztworze kwasu solnego w odniesieniu do czasu rozpuszczania. Ustalono zależności szybkości rozpuszczania od pH. Określono zmiany pH oraz stężeń Ca2+ i Mg2+ od czasu w roztworze podczas karbonatyzacji. Badano wpływ temperatury na szybkość precypitacji jonów Ca2+ w postaci stałego CaCO3. Przeprowadzono eksperymenty dla określenia kinetyki termicznego rozkładu MgCl2ź6H2O podczas pirolizy. Otrzymano wysokiej czystości tlenek magnezu o zawartości 98.86% MgO z solanki zawierającej chlorek magnezu, przy sprawności termicznej dekompozycji wynoszącej 98.10%.

12

A study on the synthesis, characterization and photocatalytic activity of TiO2 derived nanostructures

Zielińska B., Borowiak-Palen E., Kalenczuk R. J.

Materials Science Poland

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2010

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Vol. 28, No. 3

625--637

EN

Syntheses of TiO2 derived nanostructures have been conducted at 210 °C by hydrothermal reaction of commercial TiO2-P25 (Degussa, Germany) in 10 M NaOH aqueous solution. High purity of the asproduced material was confirmed by scanning and transmission electron microscope analyses. The crystallographic structure, as well as the optical and vibronic properties of this material were examined by X-ray diffraction, diffuse reflectance (DR) UV-Vis, resonance Raman spectroscopic methods, respectively. Detailed analysis of the phase composition revealed that the rod-like structures are made up of sodium tetratitanate (Na2Ti4O9). It was also observed that acid treatment of the material (hydrothermal reaction) led to a decrease in the diameters of the nanorods. Finally, the photocatalytic activity of the investigated nanostructures was examined, by observing the reaction photocatalytic decolourisation of two organic dyes (Reactive Red 198 and Reactive Black 5) under UV-light irradiation.

13

Zachowanie dodatków w procesie rafinacji pozapiecowej stali

Iwanciw J., Podorska D., Wypartowicz J.

Hutnik, Wiadomości Hutnicze

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2010

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Vol. 77, nr 4

132-139

PL

Za pomocą własnego programu komputerowego dokonano symulacji przebiegu rafinacji stali z dodatkiem glinu i tytanu, wyznaczając masę i skład chemiczny ciekłej stali, wydzieleń niemetalicznych i żużla dla ustalonej lub zmiennej temperatury. Rozpatrzono konsekwencje występowania dwóch możliwych form istnienia azotków glinu i tytanu: jako odrębnych faz i jako składników ciekłego roztworu. Równoległą analizę tego samego przypadku przeprowadzono za pomocą programu FactSage, wyznaczając kolejne stany równowagi między ciekłą stalą a fazą niemetaliczną. Stwierdzono, że azotki glinu i tytanu mogą występować tylko jako składniki roztworu tlenkowo-azotkowego, nie zaś jako odrębna faza.

EN

Authors’ computer program was employed in the simulation of the course of steel refining by means of aluminium and titanium. The mass and chemical composition of liquid steel, non-metallic precipitates and the slag were calculated at constant or variable temperature. The influence of assumed nitrides form on the results of simulation was determined. Nitrides may be considered either as separate phases or as the components of non-metallic solution. Parallel analysis of steel refining was carried out with the use of FactSage program. As a result of calculations the subsequent states of equilibrium between steel and non-metallic phase. It was found that aluminium and titanium nitrides may exist only as the components of oxide-nitride solution , not as separate phases.

14

Synthesis of nanocrystalline rutile-phase titania at low temperatures

Santos J. G., Ogasawara T., Correa R. A.

Materials Science Poland

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2009

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Vol. 27, No. 4/1

1067--1076

EN

Anatase and rutile are the predominant phases in titanium dioxide. In many cases, rutile stable phase is the desired product material, but at low temperatures methods of synthesis (aqueous route) produce metastable anatase as a major product that reverts to rutile only when heated up to 1000°C. Calcination for obtaining rutile phase is the greatest energy demanding step for titanium dioxide production by the sulphate process, and is responsible for almost 60% of total energy consumption. In this work, an innovative technique involving a sonication pre-treatment in acid medium was developed to change particle reactivity and accelerate the anatase-to-rutile transformation. Scanning electron micrographs and surface area measurements confirmed the alteration in texture and porosity of the powders. Results indicate that it is possible to obtain 100% of rutile phase at temperatures as low as 430°C.

15

Application of Combined Discrete/Finite Element Multiscale method for modelling of Mg redistribution during hot rolling of alluminium

Krzyzanowski M., Rainforth W. M.

Computer Methods in Materials Science

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2009

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Vol. 9, No. 2

271-276

EN

Numerical modelling of the stock surface layer formation has been carried out to support simulations of the reheating and breakdown rolling of the Al-Mg-Mn aluminium alloy AA3104 using a two-high laboratory mill. Prediction of the particulate phenomena taking place at the few microns thick surface layer is limited when the traditional Finite Element techniques are applied. Effectively, the numerical problem is a matter of discrete rather then continuum numerical analysis even assuming today?s level of understanding of physical events responsible for the behaviour of the stock/roll interface. The model of the stock/roll interface is a meso-part of a macro- finite-element model that is thermomechanically coupled. Corresponding linking of the modelling scales is based on transferring the corresponding boundary conditions from the macro model to the representative cell, considered as the meso- level model. This is a necessary stage for numerical analysis of fine mechanisms of the interface formation. The meso- scale model has the capacity to include very fine features of the interface such as roll asperities, scales, voids or a complicated profile of the scale/metal interface formed due to abrasion and adhesion to the work roll surface. The meso- model consists of a large number of deformable bodies that interact with each other. Each individual discrete element is of a general shape and size, and is discretised into finite elements to analyse deformability and diffusion. The transfer processes in the thin surface layer are described by the system of diffusion and the motion equations for particles integrated in time. The applied combined finite-discrete element method merges finite element tools and techniques with discrete element algorithms. Finite-element based analysis of continua is merged with discrete element-based transient dynamics, contact detection and contact interaction solutions. The results of the experimental examinations obtained for the laboratory samples indicated that the level of Mg, representing oxides dispersed within the near surface regions of the rolled specimen, was of an order of magnitude less than that observed in the reheated specimens. The numerical analysis indicated that, under the rolling conditions used, the redistribution in Mg content can arise mainly due to one or a few of the following reasons, namely: by removal of some of the thin oxide layer by abrasion and adhesion to the work roll surface; by intermixing of the small oxides (Mg) into the subsurface layer of a few microns depth; and by diffusion. Further analysis should be carried out to establish the predominant mechanisms of the surface layer formation and influence of the key hot rolling parameters.

PL

Opracowany został numeryczny model tworzenia się warstwy powierzchniowej w celu symulacji nagrzewania i wstępnego walcowania na gorąco w walcarce laboratoryjnej duo stopu Al-Mg-Mn (AA3104). Wyniki badań doświadczalnych wykazały, że struktura, morfologia oraz podatność warstwy przypowierzchniowej na nitkowatą korozję zależą mocno od głębokości warstwy bogatej w Mg i od redystrybucji tego metalicznego pierwiastka podczas walcowania na gorąco. Modelowanie tego zjawiska jest zadaniem raczej dla analizy dyskretnej niż dla numerycznego rozwiązania kontynualnego. Zastosowane w pracy podejście łączy narzędzia i techniki metody elementów skończonych z metodą dyskretną opisującą dynamikę stanów przejściowych, detekcję styku i interakcje w obszarze styku. Połączenie różnych skal w modelu opiera się na przekazywaniu odpowiednich warunków brzegowych z modelu makro do prezentatywnych komórek, traktowanych jako model mezo. Ten model mezo składa się z dużej liczby odkształcalnych ciał, które wzajemnie oddziaływają na siebie. Każdy pojedynczy dyskretny element ma ogólny kształt oraz wymiar i może być dyskretyzowany elementami skończonymi dla przeprowadzenia analizy odkształcenia i dyfuzji. Procesy transportu w cienkiej warstwie przypowierzchniowej są opisane przez układ równań dyfuzji i ruchu cząstek, które są całkowane po czasie. Numeryczna analiza wykazała że, dla pewnych warunków walcowania, wzrost zawartości Mg w wyniku redystrybucji może być wynikiem tylko jednej lub kilku następujących przyczyn: usunięcie cienkiej warstwy tlenków przez ścieranie lub adhezję do powierzchni walców; przez wymieszanie małych tlenków (Mg) w warstwie pod powierzchniowej o grubości kilku mikronów; i przez dyfuzję. Dalsza analiza powinna zostać przeprowadzona dla weryfikacji przedstawionego modelu i dla ustalenia dominujących mechanizmów tworzenia się warstwy powierzchniowej oraz wpływu podstawowych parametrów procesu walcowania na tą warstwę.

16

Spaleniowa synteza materiałów nanostrukturalnych

Cudziło S., Szala M.

Wiadomości Chemiczne

|

2006

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[Z] 60, 11-12

793-817

EN

Combustion synthesis or self-propagating high-temperature synthesis (SHS) is a well established method for preparation of many valuable compounds such as: refractory compounds (borides, carbides, nitrides, silicides), oxides (tanthalates, niobates, ferrites, cuprates), intermetallics (aluminides, germanides, nickelides) chalcogenides (sulphides, selenides, tellurides), phosphides, hydrides, and some others. The applications of these compounds can be classified as: cutting tools and polishing powders, resistive heating elements, shape-memory alloys, electrodes, coatings and thin films. Some SHS technologies have found their industrial applications. In Russia, USA and Japan, the SHS powders of inorganic compounds, ceramic insulators, high temperature heaters, shape memory alloy wire, cutting inserts, etc, are produced on an industrial scale. However, it was thought that only large particles (several microns and above) could be obtained by the SHS method [1-3]. It was found recently (Nersisyan et al., 2003-2005), that if the reaction occurs in a medium of molten salt (basically alkali metal halide) and has moderate exothermicity, nanometric size titanium carbide and some of transition metals (Ti, Ta, Nb, Mo) could be obtained by utilization of SHS method. Moreover Huczko at al. (2005) reported that silicon carbide single-crystals in the form of nanofibers and spherical multi-walled carbon nanoparticles and encapsulates could be prepared through the defluorination of poly(tetrafluoroethene) with silicon-containing precursors using the combustion synthesis route. Finally, in 2005, Koch published complete results of a thermodynamic analysis of self-sustaining reaction of fluorinated graphite with magnesium, and reported on detection of single walled carbon nanotubes and carbon nano carpet rolls in the combustion products. This discovery of great importance was patented as a new method of synthesis of carbon allotropes (fullerenes, carbon nanotubes) and various carbon encapsulates. Undoubtedly, it has been demonstrated that SHS offers great potential for generating nanomaterials, including 1D inorganic and carbon nonostructures. In this review, we discuss the recent developments in the field of combustion synthesis, with special emphasis on the preparation of nanomaterials by low-temperature combustion synthesis (LCS), reductive dehalogenation of halocarbons, and sol-gel combustion synthesis (SCS).

17

Investigation of structural, optical and lasing properties of YAG:Yb single crystals

Świrkowicz M., Skórczakowski M., Jabczyński J., Bajor A., Tymicki E., Kaczmarek B., Łukasiewicz T.

Opto-Electronics Review

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2005

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Vol. 13, No. 3

213-220

EN

Single crystals of yttrium aluminium garnet (YAG) doped with ytterbium ions of up to 30 at.% were grown by the Czochralski method. Using the growth rate from 1 to 3 mm/h, and the rotation rate from 15 to 30 rpm, single crystals with diameters of up to 22 mm and lengths up to 85 mm were obtained. Using the inductively coupled plasma n optical emission spectroscopy (ICP-OES) method, Yb distribution coefficient was determined to be equal to 1.10±0.02. The following methods: optical absorption spectroscopy, plane and circular polariscope, electron probe microanalysis (EPMA) to determine the radial distribution of Yb ions, X-ray diffraction methods to determine the lattice constant were used. Etch pit density distribution and lasing properties were also investigated. Samples of YAG:Yb crystals with Yb ions contents of 3, 5, 7, and 10 at.% were pumped by 940 nm laser diode for their lasing properties. The best lasing slope efficiency of 40% with respect to the absorbed pump power was achieved at 5 at.% Yb content. The lowest threshold of 2.5 W of the absorbed pump power was observed, however, for a 7 at.% Yb doped sample in quasi hemispherical resonator configuration. These investigations have been found to be in good agreement with polariscopic observations, showing a certain decrease in optical homogeneity with increase in Yb content.

18

X-ray photoelectron spectroscopy studies of PrAlO3 crystals before and after thermal treatment

Kruczek M., Talik E., Pawlak D., Łukasiewicz T.

Optica Applicata

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2005

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Vol. 35, nr 3

347-328

EN

The as-grown PrA103 single crystals grown by the Czochralski method are brown colored and after annealing in the reducing atmosphere (20%) H2/N2 they change the color to green. The X-ray photoelectron spectroscopy was used to study the chemical composition and electronic structure of PrAlO3 single crystals before and after the thermal treatment. The core electron lines of praseodymium, aluminum and oxygen were measured and deconvoluted into the synthetic peaks to determine the chemical shifts. The mixed ionic and covalent character of bonds was found. The praseodymium valency may influence the coloration of the PrAlO3 crystal. In the as-grown sample an additional Pr 3d3/2 peak at about 965 eV has higher intensity than that in the annealed one and is attributed to the presence of Pr4+ ions. The measurements showed the reduction of oxygen during thermal treatment and that interstitial oxygen was not removed in this process.

19

Analiza skutków ultrapłytkiej implantacji jonów azotu w plazmie w cz. (13,56 MHz)

Bienek T., Beck R. B., Jakubowski A., Kudła A.

Elektronika : konstrukcje, technologie, zastosowania

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2005

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Vol. 46, nr 2-3

9-10

PL

Przedstawione w pracy eksperymenty są częścią szerszych studiów mających na celu zbadanie możliwości zastosowania jednocześnie obu etapów wytwarzania warstwy dielektrycznej, np. ultrapłytkiej implantacji jonów azotu i utleniania w jednym stanowisku technologicznym.

EN

Presented in this work experiments are a part of a broader study that examines the possibility of conducting both stages of creation of the dielectric (e.g. ultra-shallow nitrogen implantation and silicon oxidation) in one technological reactor.

20

Induction skull melting of oxides and glasses

Kudryash M., Behrens T., Nacke B.

Archives of Electrical Engineering

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2005

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Vol. 54, nr 4

417-423

EN

A multi-functional installation for induction skull melting of oxides is described. The installation allows realizing wide range of processes like synthesis of high purity oxide materials, single crystal growing, investigation of phase diagrams, melting of glasses and ceramics. Melting of low conductive oxide materials by high frequency electromagnetic field provides overheating the melt on 500 K and higher above the melting point with extremely low pollution of the material. A high frequency transistor generator accomplishes the installation. One inductor-crucible and two cold crucibles of various volumes were used for the research. Melting of zirconium oxide, single crystals growing stabilized zirconium oxide, melting of YBCO-based superconductor as well as a mix of zirconium and aluminium oxides have been carried out in the cold crucibles, while the inductor crucible was used for low temperature glass melting. Energy balance of melting process for different oxides and glasses is presented. Several ways how to start the melting process in cold crucible or inductor-crucible are described.

PL

W artykule opisano wieloczynnościową instalację do topienia indukcyjnego tlenków i szkła w piecu-wzbudniku. Instalacja pozwala realizować szeroką gamę procesów takich jak synteza wysokiej czystości tlenków metali, wzrost monokryształów, badanie wykresów fazowych, topienie szkła i ceramiki. Topienie nisko-przewodzących tlenków przy wykorzystaniu pola elektromagnetycznego wielkiej częstotliwości prowadzi do nagrzania kąpieli do temperatury o 500 K powyżej temperatury topnienia przy niezmiernie małym zanieczyszczeniu materiału. Instalacja jest zasilana przy użyciu generatora tranzystorowego wielkiej częstotliwości. Do badań użyto jednego pieca-wzbudnika oraz dwóch pieców indukcyjnych z zimnym tyglem o różnych objętościach. Topienie tlenku cyrkonu, wzrost monokryształów stabilizowany tlenkiem cyrkonu, topienie nadprzewodników na bazie YBCO jak również mieszaniny tlenków cyrkonu i aluminium przeprowadzono w piecach z zimnym tyglem, podczas gdy piec-wzbudnik został użyty do topienia szkła. Przedstawiono bilans energetyczny procesu topienia tlenków oraz szkła. Opisano szereg sposobów rozpoczęcia procesu topienia w piecu z zimnym tyglem oraz w piecu-wzbudniku.