Ammonium Jarosite waste released from zinc extraction process possess serious environmental problem due to the presence of toxic metals such as Pb, Cd, Zn, As etc. Its disposal in open tailing damps has become a major environmental concern with contamination effects of water, soil and vegetation. The current paper considers the ammonium jarosite waste in Mitrovica Industrial Park, Kosovo in order to evaluate the characteristics of jarosite waste, identify the potential environmental impacts and understand its potential for recycling or utilization as a challenge for development of positive "green" image environmental protection and sustainable hazard waste management in future. XRD, SEM and TG/DTA were used to analyze the characterization features of ammonium jarosite. The results give an initial understanding of the ammonium jarosite strengths as recycled material in construction industry. The utilization options showed very useful contribution towards proper environmental, social and economic management development.
Key word: ammonium jarosite, characteristics, utilization.

Titanium (Ti), the fourth richest metallic element in the earth's crust, is widely used and researched in a variety of applications such as aerospace, marine, and medicine due to its excellent specific strength and corrosion resistance. Recently, many researchers have focused on the refining process of Ti because the global production of Ti is low compared to iron and aluminium and recycling Ti waste is crucial. The important step in refining Ti is the deoxidation process. The oxygen dissolved in Ti reduces the ductility and fatigue resistance of the material, which consequently causes poor forming ability. However, Ti's inherent properties such as its high melting point (1668 C) and oxygen affinity at high temperatures cause the deoxidation process to be difficult. Particularly, the Ti scrap and chip have high oxygen contents owing to hot processing and cutting. In this study, the effects of Ca which has higher oxygen affinity than titanium on deoxidation of titanium and the rate of deoxidation in terms of time were evaluated. The Ti scrap was melted using electro-magnetic induction and deoxidized with calcium (Ca) granules.
Keywords: Titanium, Deoxidation, Oxygen, Refining mechanism

<br />Nb-Si composites with a high melting point and low density are of interest as a candidate material for use in aircraft engines. However, one major limitation in the application of composites Nb-Si is their poor corrosion resistance at elevated temperatures. The corrosion resistance of Nb-Si composites can be improved by alloying elements such as yttrium. This paper studied the effect of yttrium on the oxidation of eutectic alloy Nb-Si at 25-1000o in air by thermogravimetric method, X-ray diffraction analysis and electron-probe microanalysis. The oxidation products are the oxides of silicon and niobium, which are fixed at a temperature above 600oC. The positive effects of yttrium on the corrosion resistance of Nb-Si eutectic alloy up to 700oC shown. The content in the samples of more than 3%Y increases the oxidation rate of alloys and reduces their heat resistance at heated in air.

In this talk, we review the characteristic features of icosahedral cluster solids, metallic-covalent bonding conversion (MCBC) and the thermoelectric properties of Al-based icosahedral quasicrystals and approximants. MCBC is clearly distinguishable from and closely related to the well-known metal-insulator transition. This unique bonding conversion has been experimentally verified in 1/1-AlReSi and 1/0-Al12Re approximants by the maximum entropy method and Rietveld refinement for powder x-ray diffraction data and is caused by a central atom inside the icosahedral clusters. This helps to understand pseudogap formation in the vicinity of the Fermi energy and establish a guiding principle for tuning the thermoelectric properties. From the electron density distribution analysis, rigid heavy clusters weakly bonded with glue atoms are observed in the 1/1-AlReSi approximant crystal, whose physical properties are close to icosahedral Al-Pd-TM (TM: Re, Mn) quasicrystals. They are considered to be an intermediate state among the three typical solids: metals, covalently bonded networks (semiconductor) and molecular solids. Using the above picture and detailed effective mass analysis, we propose a guiding principle of weakly bonded rigid heavy clusters to increase the thermoelectric figure of merit (ZT) by optimizing the bond strengths of intra- and intericosahedral clusters. Through element substitutions that mainly weaken the inter-cluster bonds, a dramatic increase of ZT from less than 0.01 to 0.26 was achieved. To further increase ZT, materials should form a real gap to obtain a higher Seebeck coefficient.

The aim of this paper is to study the corrosion action processes on the surface morphology, crystal structure and magnetic characteristics changes of various grades of stainless steel. Corrosion studies were carried out on inox (W1.4783) and inocorr (W1.4781) steels by potentiodynamic method in solutions of CHCl-Urea, ChCl-EG and ChCl-AOx at T ~ 380 K. The crystal structure was studied in CuK(alfa) - radiation in the 3 <= 2Tetta <=150 angles range at room temperature. The specific magnetization was investigated by ponderomotive method in non-destructive regime in the 80 - 1100 K temperature range. The elemental composition, elements distribution maps, coatings surface images are obtained using X-ray microanalyzer JXA 8100 with energy-prefix INCA, a scanning electron microscope of high resolution Hitachi S5500. It is found that when we use corrosive action, it generally does not affect the crystal structure of the stainless steel. The structure and magnetic properties changes of the surface steel layers are determined not only by the characteristics of corrosion media. The surface of W1.4873 steel is relatively resistant to composition ChCl-EG but weak-stable to the expose of ChCl-urea ionic liquid and especially to ChCl-AOx. Corrosive action to W.14781 steel has practically no effect on the specific magnetization value and Curie temperature, while greatly reducing the magnetization of W.14783 steel at a temperature ~ 80 K from 12 A*m2*kg-1 to 5 A*m2*kg-1 and the Curie temperature by 30 K. The images obtained using an electron microscope show that in the initial state a steel surface comprises defects, which become corrosion centers. The results of the study of the specific magnetization temperature dependences indicate that the magnetic properties of steels with a high content of nickel are more resistant to corrosion.

The goal of this paper is to study the effect of high temperatures action on the specific magnetization value of 12X18H9 and 12X18H9T steels. Steels in form of plates 10 x 5 mm with thickness of 5, 6, 8 and 10 mm widely used in nuclear engineering were selected as samples for research. Experimental techniques, such as elemental analysis, diffraction backscattered electrons, X-ray analysis, measurement of specific magnetization in the 80 - 1100 K temperature range in a magnetic field with the induction of 0.86 T, the study of specific magnetization in a magnetic field with B = 14 T at a temperature of 300 K and the magnetization measurement with magnetodynamic type converter were applied. The X-ray diffraction studies have shown that the main components of stainless steels 12X18H9 and 12X18H9T are FeNi and NiCrFe phase. It was found that the main phase is ferromagnetic FeNi. The presence of FeNi phase was confirmed by diffraction backscattered electrons method (EBSD). The correlation of the specific magnetization value with the content of FeNi phase amount was determined. It was revealed that the magnetization in saturation of the test steels is practically absent in magnetic fields with induction up to 14 T. It was shown that the magnetic properties of the studied samples are due to both particles with ferromagnetic properties and paramagnetic clusters with superparamagnetic state characteristics. The comparison of the results of the specific magnetization measurement of 12X18H9T and 12X18H9 steel with a magnetodynamic converter data at room temperature shows that this method has a high sensitivity (0.016% in volume) and may be used for the quantitative determination of the ferromagnetic component.

This paper performed thermodynamic calculations on the Ln2O3-BaO (Ln=La, Nd, Sm) binary system by CALPHAD approach. A regular substitution solution model was adopted to describe the liquid phase. The Neumann-Kopp rule was used to describe the compounds existing in the systems. The compounds were treated as stoichiometric. The thermodynamic parameters for each phase in the Ln2O3-BaO system were reassessed by using available experimental information on phase diagram and thermodynamic properties, which were used to calculate the phase diagram and thermodynamic properties of the Ln2O3-BaO system. Comparisons between the present calculations with the literature data showed that all reliable experimental information was satisfactorily accounted for by the present thermodynamic description. The discrepancy from the literature calculation is also illustrated.

A basic insight into the atomic structures of some important alloy forming elements, like magnesium, aluminum, titanium, niobium etc will be presented in terms of their covalent radii, Bohr radii, nuclear and electron radii and their relation to the Golden ratio, using the data provided earlier for the elements of the Periodic Table. It is interesting to point out that for the elements of Group A: Rb (1.72, 2.79), Cs (1.85, 3.02), Mg (0.94, 1.60), Ca (1.18, 1.98), Sr (1.26, 2.15), Al (1.20, 2.02), P (0.69, 1.11), As (0.74, 1.25), He (0.29, 0.46) and Group B: Pd (0.86, 1.38), where the 1st and 2nd terms in the parenthesis are their Bohr radii, a(B) (from 1st ionization potentials) and covalent radii R(cov) in A…, respectively, the ratio, R(cov)/a(B) is close to the Golden ratio (1.62). These and other relations, it is hoped, will provide deeper insights into the understanding of the bonding and alloy formation of different materials and help in designing materials depending on their intended purpose.

In this paper, we have investigated the formation of Al-Mn alloy films and the effect of annealing on the structural. The Al1-xMnx thin films with different Mn concentration were prepared using a DC magnetron sputtering method.
The microstructures of as-deposited films were then compared to those observed after thermal annealing treatment in vacuum at 500A°C for 1 h. The alloys were characterized by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD)
The XRD results described above reveal the presence of amorphous structure for untreated samples with high concentrations of manganese and the transformation from the amorphous state to the crystalline one by annealing.
After the annealing treatment we have observed, at manganese concentration between 10 to 32 at.%, the phases predicted by the equilibrium diagram, such as Al, Al-Mn and A16Mn.
At higher manganese compositions (a‰ˆ 41 wt %) the metastable crystal structure of Al8Mn5 phase is obtained.

Powder metallurgy is a leading area in materials science, the preferred route for the production of materials with specific properties, such as cutting tools and other wear resistant parts.
Among the powder manufacturing technologies, mechanosynthesis plays an important role because it allows to form alloys in solid phase from immiscible components.
The synthesis of tungsten carbide powder by direct carburizing of tungsten oxide in one step, using the mechanical alloying method, is possible but requires very tough conditions for milling installation. Tungsten carbide is generally produced by chemical processes and subsequently subjected to long grinding processes to obtain the desired granulometry.
In order to improve this grinding process, we subjected a commercial tungsten carbide powder to milling in a planetary mill Pulverisette 7 Premium line at rotational speeds of 300, 400, 500 and 600 rpm using balls of various sizes for maximum 10 hours. The resulting powder was analyzed by scanning electron microscopy and laser granulometry. After different periods of grinding, we observe a reduction in size of the tungsten carbide particles, at least 50% of the powder having a grain size smaller than 1 Aµm.

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