Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 10
items per page: 25 50 75
Sort by:

Abstract

In this paper, study the preparation of Y-Fe alloy by reduction-diffusion process, which is novel technique for producing an alloy from its ores directly at different temperatures. From this work, investigates the particles size and morphology structure of alloy by X-Ray Diffraction (XRD), Energy dispersive-X-ray analyzer (EDAX) and Scanning Electron Microscope (SEM) respectively. Here study the thermodynamics of property of system such as Gibbs free energy and reaction kinetics of system respectively. The Vibrating Sample magnetometer (VSM) is used to study the magnetic properties of alloy such as cocerviety, saturation magnetization and retentivity.
Go to article

Abstract

W artykule zbadano możliwość wykorzystania popiołów lotnych klasy C (otrzymywanych w wyniku spalania węgla brunatnego w kotle pyłowym) i F (otrzymywanych w wyniku spalania węgla kamiennego metodą konwencjonalną) jako substratów do syntezy materiału zeolitowego z grupy filipsytu. W tym celu przeprowadzono szereg syntez hydrotermalnych z wykorzystaniem reagentów takich jak wodorotlenek sodu (NaOH) oraz bromek tetrapropyloamoniowy (TPABr). W wyniku reakcji otrzymano docelowy materiał zeolitowy, zarówno z popiołu klasy C, jak i F. Otrzymane produkty syntezy, jak też popiołowe substraty reakcji, poddano charakterystyce chemicznej i mineralogicznej. Badania wykazały, że popiół lotny powstały z węgla brunatnego i kamiennego może być substratem w reakcjach syntez zeolitu, jakim jest filipsyt. Analiza porównawcza dyfraktogramów rentgenowskich produktów z obu typów popiołów wykazała, że lepszym substratem jest popiół klasy C otrzymywany w wyniku spalania węgla brunatnego w kotle pyłowym (w reakcji syntezy otrzymano lepiej wykształcone formy zeolitowe). W pracy dokonano także analizy literaturowej potencjalnych kierunków zastosowania filipsytu w inżynierii i ochronie środowiska. Na podstawie zweryfikowanych danych stwierdzono, iż dalszym kierunkiem badań będzie analiza możliwości wykorzystania otrzymanych materiałów jako potencjalnych sorbentów amoniaku.
Go to article

Abstract

The article presents the results of research concerning to AlCu4MgSi alloy ingots produced using horizontal continuous casting process. The presented research was focused on the precise determination of phase composition of the precipitates formed during the solidification of ingots and the analysis of their thermal stability. In order to assess the morphology of precipitates in the AlCu4MgSi alloy, data obtained by using a computer simulation of thermodynamic phenomena were compiled with results obtained using advanced research techniques, i.e. High-temperature X-ray diffraction (HT-XRD), SEM-EDS, Thermal and derivative analysis (TDA) and Glow discharge optical emission spectroscopy (GD OES). SEM observations and analysis of chemical composition in micro-areas showed that the precipitates are mainly intermetallic θ-Al2Cu and β-Mg2Si phases, and also presence of Al19Fe4MnSi2 intermetallic phase was confirmed by X-ray diffraction studies. Based on the prepared Thermo-Calc simulation data, high-temperature X-ray diffraction measurements were conducted.
Go to article

Abstract

The paper is concerned with comparing the methods for determining the ferrite content in castings from duplex stainless steels. It uses Schaeffler diagram, empirical formula based calculation, image analysis of metallographic sample, X-ray diffraction and measurement with a feritscope. The influence of wall thickness of the casting on the ferrite content was tested too. The results of the experiments show that the casting thickness of 25 or 60 mm does not have a significant effect on the measured amount of ferrite. The image analysis of metallographic sample and the measurement with the feritscope appear to be the most suitable methods. On the contrary, predictive methods, such as Schaeffler diagram or empirical formula based calculation are only indicative and cannot replace the real measurements. X-ray diffraction seems to be the least suitable measuring method. Values of ferrite content measured in such a way often deviated from the values measured by image analysis and with feritscope.
Go to article

Abstract

The subject of the paper is structural stability of the Zn-26 wt.% Al binary alloys doped with 2.2 wt.% Cu or 1.6 wt.% Ti addition. The structural stability of Zn-Al alloys with increased Al content is connected with stability of solid solution of zinc in aluminium α', which is the main component of these alloys microstructure. Such a solution undergoes phase transformations which are accompanied, among others, by changes in dimensions and strength properties. The structural stability of the ZnAL26Cu2.2 and ZnAl26Ti1.6 alloys was investigated using XRD examinations during long term natural ageing after casting, as well as during long term natural ageing after super-saturation and quenching. On the basis of the performed examinations it was stated that small Ti addition to the binary ZnAl25 alloy, apart from structure refinement, accelerates decomposition of the primary α' phase giving stable structure in a shorter period of time in comparison with the alloy without Ti addition. Addition of Ti in amount of 1.6 wt.%, totally replacing Cu, allows obtaining stable structure and dimensions and allows avoiding structural instability caused by the metastable ε−CuZn4 phase present in the ZnAl26Cu2.2 alloy.
Go to article

Abstract

Equal-channel angular pressing (ECAP) was used as a technique for severe plastic deformation (SPD) on Al alloy AA3004. This technique produced fully dense materials of refined grain structure to sub-micrometer dimensions and advanced mechanical properties. The ECAP processing of samples was conducted as 1 to 4 passes through the die at room temperature. We present the results of the studied homogeneity evolution with the ECAP treatment. Furthermore, a Scanning Electron Microscope (SEM) was used for examination of the microstructure changes in samples undergone from 1 to 4 passes. The microhardness-HV increased upon each ECAP pass. The resulting micro-hardness evolution was attributed to crystalline microstructure modifications, such as the d-spacing (studied by X-ray Diffraction-XRD) depending on the number of ECAP pressings. The microcrystalline changes (grain refining evaluated from the Scanning Electron Microscopy – SEM images) were found to be related to the HV, following the Hall-Petch equation.
Go to article

Abstract

Zinc is present in electric arc furnace dust (EAFD) mainly in two basic minerals, namely as franklinite ZnFe2O4 and/or zincite ZnO. While zincite is relatively reactive and easily treatable, franklinite is considerably refractory, which causes problems during EAFD processing. In this work EAFD containing 18.53% Zn was leached in water solution of ammonium carbonate. This leaching solution selectively leaches zincite, while franklinite is refractory and stable against leaching in this case. The temperature dependence of zinc leaching from EAFD was studied and the activation energy EA was determined by two methods: 1.) classically based on zinc chemical analyses from the leaching solution and 2.) by using of X-Ray diffraction qualitative phase analyses of leaching residues. The determined values of activation energies 37.41 and 38.55 kJmol–1 match perfectly, which show the excellent possibility of using X-Ray diffraction toward the study of leaching kinetics at properly chosen experimental conditions. The important result is the determination of the amount zincite and franklinite in EAFD, which is not possible by using of classical chemical methods.
Go to article

Abstract

Nano technology is an emerging field of interest for civil engineering application. Among the nano materials presently used in concrete, nano-silica possess more pozzolanic nature. It has the capability to react with the free lime during the cement hydration and forms additional C-S-H gel giving strength, impermeability and durability to concrete. Present paper investigates the effects of addition of nano silica in normal strength concrete. Three types of nano-silica in the form of nano suspension having different amount of silica content have been investigated. Mix design has been carried out by using particle packing method. X-Ray diffraction (XRD) analysis has been carried out to find the chemical composition of control concrete and nano modified concrete. Further, experimental investigations have been carried out to characterize the mechanical behaviour in compression, tension and flexure. It has been observed that the addition of nano-silica in normal strength concrete increased the compressive strength and decreased the spilt tensile strength and flexural strength. Also, Rapid chloride permeability test (RCPT) has been conducted to know the chloride permeability of control concrete, nano modified concrete, and nano coated concrete. It has been observed that the chloride permeability is less for nano coated concrete.
Go to article

Abstract

The aim of these studies was to obtain single phase cubic modification of Li7La3Zr2O12 by mechanical milling and annealing of La(OH)3, Li2CO3 and ZrO2 powder mixture. Fritsch P5 planetary ball mill, Rigaku MiniFlex II X-ray diffractometer, Setaram TG-DSC 1500 analyser and FEI Titan 80-300 transmission electron microscope were used for sample preparation and investigations. The applied milling and annealing parameters allowed to obtain the significant contribution of c-Li7La3Zr2O12 in the sample structure, reaching 90%. Thermal measurements revealed more complex reactions requiring further studies.
Go to article

Abstract

The aim of the paper is the residual stress analysis of AlSi10Mg material fabricated by selective laser melting (SLM). The SLM technique allows to product of complex geometries based on three-dimensional model, in which stiffness and porosity can be precisely designed for specific uses. As the studied material, there were chosen solid samples built in two different directions: parallel (P-L) and perpendicular (P-R) to the tested surface and cellular lattice built in perpendicular direction, as well. In the paper, for the complex characterization of obtained materials, the phase analysis, residual stress and texture studies were performed. The classical non-destructive sin2ψ method was used to measure the residual stress measurements. The final products, both solid sample and cellular lattice, have a homogeneous phase composition and consist of solid solution Al(Si) (Fm-3m) type, Si (Fd-3m) and Mg2Si (Pnma). The obtained values of the crystallite size are in a range of 1000 Å for Al(Si), 130-180 Å for Si phase. For Mg2Si phase, the crystallite sizes depend on sintering process, they are 800 Å for solid samples and 107 Å for cellular lattice. The residual stress results have the compressive character and they are in a range from –5 to –15 MPa.
Go to article

This page uses 'cookies'. Learn more