Investigation of solidification behavior of the Sn-rich ternary Sn-Bi-Zn alloys

Solidification properties and microstructure of six as-cast Sn-Bi-Zn alloys with 80 at.% of Sn and variable contents of Bi and Zn were experimentally investigated using the scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and differential scanning calorimetry (DSC). The experimentally obtained results were compared with predicted phase equilibria according to the calculation of phase diagram (CALPHAD) method and by the Scheil solidification simulation.

EXAMPLES OF LCA METHODOLOGY IMPLEMENTATION IN STEEL INDUSTRY

Steel industry kept pace with actual trends for environmental protection in many ways – through different technological improvements considering environment protection, important share of recycling in the steel production, design of so called “eco-steels”, materials designed according to recent environmental directives and legislatives, etc. In the frame of steel production monitoring, LCA methodology is very important for obtaining an accurate environmental picture of a process, due to the fact that the process should be evaluated over its entire life cycle. A number of tools and methodologies have been developed in recent years to assess the potential environmental impacts associated with a product, process or activity during its entire life cycle. The examples of Life Cycle Assessment (LCA) are used by large steel industrial companies as potentially helpful tool for improving the production processes, efficiency of resource utilization and significantly reduction of waste generation and emissions are presented in this paper

Thermal analysis and kinetics of the chalcopyrite-pyrite concentrate oxidation process

The paper presents the results of experimental investigation of the chalcopyrite-pyrite concentrate oxidation in the air. Characterisation of the initial sample and oxidation products was done by ICP-AES, XRD, EDXRF methods. Phase stability diagrams were constructed for Cu-Fe-S-O system at 25, 450, 650 and 900 °C. Equilibrium composition of the charge for the optimal oxidation process was calculated. DTA-TG analysis was used for monitoring the oxidation process. Kinetic parameters in non-isothermal conditions were determined, based on Kissinger and Ozawa methods.Values of activation energies showed that all stages of the oxidation process occur in the kinetic field

Kalorimetrijsko ispitivanje tekućih Ga-Me (Sn, Zn) legura Oelsenovom metodom

The results of calorimetric investigation of binary, liquid Ga-Me (Sn, Zn) alloys are presented in this paper. According to constructed space enthalpy diagram and enthalpy isotherm diagram, activities, activity coefficients and other partial and integral molar quantities were determined at different temperatures. Also, comparison was made with existing literature data

Phase diagram investigation and characterization of alloys in Bi-Ga10Sb90 section of Ga-Bi-Sb system

The results of phase equilibria investigation and characterization of the alloys in the Bi-Ga10Sb90 section of Ga-Bi-Sb system are presented in this paper. Phase diagram of the mentioned section has been calculated according to CALPHAD model, using Pandat software. In the frame of alloys characterization, structural, mechanical and electrical characteristics were determined using SEM-EDX analysis, microhardness and electroconductivity measurements

Thermodynamic and Structural Investigation of the Ag-In-Sb System

The Ag-In-Sb ternary system presents one of the possible lead-free solder candidates. Therefore, the results of thermodynamic study of the alloys in the Ag-In-Sb alloys, obtained using general solution model, are presented in the paper. Obtained data for partial and integral molar thermodynamic quantities in the temperature interval 1000-1200K are given. The characterization of these alloys have been done using DTA, XRD, SEM and optic microscopy, which enabled the construction of the Ag-In-Sb phase diagram in the concentration range up to 60 wt. % Ag

Eco-friendly Elderberry based sorbent for removing Pb2+ ions from aqueous solutions

Elderberry (Sambucus nigra) pith was modified with polyethyleneimine (PEI) in order to improve the adsorption properties. Characterization of both dried Sambucus nigra pith (DSNP) and amino modification of elderberry pith with branched PEI (PEI/DSNP) was performed by: Fourier-transform infrared spectroscopy (FTIR), optical microscopy, and porosity determination. The amine and ester number, as well as acid value, were determined on DSNP and PEI/DSNP samples using standard volumetric methods. The samples were used as adsorbents for Pb2+ ions from an aqueous solution in a batch system. The obtained results were fitted using suitable equilibrium isotherm and kinetic models. The maximum adsorption capacity for Pb2+ ions on DSNP and aminаted sample, obtained using Langmuir adsorption isotherm at 298 K, are 18.9 and 47.8 mg g-1, respectively. Based on the kinetic studies, the adsorption process follows the pseudo second-order model. Thermodynamic parameters showed that the adsorption process is endothermic and spontaneous. In general, the overall adsorption process was improved by modifying starting material with branched PEI modifier by introducing large numbers of amino functionalities having high affinity to cations

EFECTS OF CHEMICAL COMPOSITION ON THE MICROSTRUCTURE AND PROPERTIES OF THE CU-Ge-Sb ALLOYS

In the current study a ternary Cu-Ge-Sb system has been experimentally assessed. Chemical and phase compositions of the alloy samples from three vertical sections Cu-GeSb, Ge-CuSb and SbCuGe were studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) and confirmed by X-ray diffraction analysis (XRD). Hardness of the alloys was measured by Brinell method while hardness of phases was measured using micro Vickers method. Electrical conductivity of the studied alloys was measured using eddy current instrument. Based on experimentally determined values iso-lines of hardness and electrical conductivity for the whole ternary system were calculated using assumed mathematical models

Study of electrical conductivity and hardness of the alloys of ternary Bi-Sb-Zn system and calculation of isothermal section at 298 K

Considering the importance of the lead-free solders, alloys of ternary Bi-Sb-Zn system were characterized by microstructural SEM-EDS and optical microscopy analysis, Brinell hardness tests and electrical conductivity measurements. Isothermal cross section at 298 K was calculated using CALPHAD method and PANDAT 8.1 software package. The phases on calculated cross sections were found to be in a good agreement with experimentally determined phase compositions in analyzed microstructures