Phase Transformation in Granular Alloys of Cu2S-Ni3S2-Na2S System

2014 ◽  
Vol 353 ◽  
pp. 263-268
Author(s):  
Evgeny N. Selivanov ◽  
L.Yu. Udoeva ◽  
N.I. Selmenskich
Keyword(s):  
Solid Solution ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Hydrometallurgical Processing ◽  
Degree Of Separation ◽  
Large Particles ◽  
Dendrite Solidification ◽  
Sulfide Melt ◽  
Two Phases ◽  
Granular Alloys

The effect of Na2S on the phase composition and microstructure of tempered Cu2S-Ni3S2 alloys was studied by X-ray diffraction, optical microscopy and electron probe microanalysis (EPMA). It was found that quick crystallization of the sulfide melt leads to separation into two phases - Ni3S2 and a solid solution of Cu2S with Na2Cu4S5, moreover, nickel is concentrated in large particles and copper – in small ones. In contrast to the fine dendrite solidification of granular Cu2S-Ni3S2 alloys, in the ternary system there is a well-defined two-phase microstructure with rounded borders of the interface. Friability and a low microhardness of Cu2S - Na2Cu4S5 solid solution provide an autodecomposition of the sulfides melt by quenching into water (granulation). The degree of separation of copper and nickel depends on the overheating temperature and a quantity of Na2S in melt. The results can be used to hydrometallurgical processing of copper-nickel convert matt.

Phase Equilibrium of Mg-Nd-Zn System near Mg-Nd Side at 400°C

2016 ◽  
Vol 873 ◽  
pp. 18-22
Author(s):  
Ming Li Huang ◽  
Xue Shen ◽  
Hong Xiao Li
Keyword(s):  
Solid Solution ◽  
Phase Equilibrium ◽  
Ternary Isothermal Section ◽  
Phase Region ◽  
X Ray Diffraction ◽  
Maximum Solubility ◽  
Two Phase ◽  
Solubility Range ◽  
Three Phase ◽  
Equilibrium Alloys

The equilibrium alloys closed to Mg-Nd side in the Mg-rich corner of the Mg-Zn-Nd system at 400°C have been investigated by scanning electron microscopy, electron probe microanalysis and X-ray diffraction. The binary solid solutions Mg12Nd and Mg3Nd with the solubility of Zn have been identified. The maximum solubility of Zn in Mg12Nd is 4.8at%, and Mg12Nd phase can be in equilibrium with Mg solid solution. However, only when the solubility range of Zn in 26at%~32.2at%, Mg3Nd can be in two-phase equilibrium with Mg solid solution. As the results, two two-phase regions as Mg+Mg12Nd and Mg+Mg3Nd and a three-phase region as Mg+Mg12Nd+Mg3Nd in Mg-Nd-Zn ternary isothermal section at 400°C have been identified.

Structural and phase equilibria studies in the system Pt-Fe-Cu and the occurrence of tulameenite (Pt2FeCu)

1985 ◽  
Vol 49 (353) ◽  
pp. 547-554 ◽  
Author(s):  
M. Shahmiri ◽  
S. Murphy ◽  
D. J. Vaughan
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Critical Temperature ◽  
Grain Boundary ◽  
Phase Region ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Slow Cooling ◽  
X Ray ◽  
Diffraction Patterns

AbstractThe crystal structure and compositional limits of the ternary compound Pt2FeCu (tulameenite), formed either by quenching from above the critical temperature of 1178°C or by slow cooling, have been investigated using X-ray diffraction, transmission electron microscopy, differential thermal analysis and electron probe microanalysis.The crystal structure of Pt2FeCu, established using electron density maps constructed from the measured and calculated intensities of X-ray diffraction patterns of powdered specimens, has the (000) and (½½0) lattice sites occupied by Pt atoms and the (½0½) and (0½½) sites occupied by either Cu or Fe atoms in a random manner. The resulting face-centred tetragonal structure undergoes a disordering transformation at the critical temperature to a postulated non-quenchable face-centred cubic structure. Stresses on quenching, arising from the ordering reaction, are relieved by twinning along {101} planes or by recrystallization along with deformation twinning; always involving grain boundary fracturing.Phase relations in the system Pt-Fe-Cu have been investigated through the construction of isothermal sections at 1000 and 600°C. At 1000°C there is an extensive single phase region of solid solution around Pt2FeCu and extending to the binary composition PtFe. At 600°C the composition Pt2FeCu lies just outside this now reduced area of solid solution in a two-phase field. Comparison of the experimental results with data for tulameenite suggests that some observed compositions may be metastably preserved. The occurrence of fine veinlets of silicate or other gangue minerals in tulameenite is suggested to result from grain boundary fracturing on cooling below the critical temperature of 1178°C and to be evidence of a magmatic origin.

Two-Phase Structure of Fluorinated Powdered Silica Resulting from Deep Processing of Rice Wastes

2018 ◽  
Vol 7 (1) ◽  
pp. 38-44 ◽  
Author(s):  
А. Рашковский ◽  
A. Rashkovskiy ◽  
Е. Политова ◽  
E. Politova ◽  
А. Меркушкин ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Physicochemical Analysis ◽  
Nano Particles ◽  
Deep Processing ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Inductively Coupled ◽  
Two Phases

In this investigation the structure of «green» silica maid with rice husk has been studied by methods of physicochemical analysis. By method of X-ray diffraction it has been found that the samples of «green» silica powders are completely amorphous, and the observed amorphous halo consists of two components. By method of scanning electron microscopy it has been revealed that nano-particles of «green» SiO2 can form agglomerates and microstructures with dimensions from 0,1 to 500 microns, containing numerous pores, which presence has been confirmed by sorption measurements. By method of mass spectrometry with inductively coupled plasma has been found the presence of aluminum, titanium and nickel mechanical impurities in the «green» SiO2 powders. By method of X-ray photoelectron spectroscopy significant amount of fluorine atoms in «green» silica (up to 5% (at.)) has been revealed, which could be introduced in SiO2 in the process of its preparation. In such a case, it was found that fluorine interacts with «green» silica by means of two mechanisms, leading to appearance of two phases within fluorinated powders of «green» SiO2.

Thermodynamic Rationalization of the Microstructures of CrFeNi & CuCrFeNi Alloys

2012 ◽  
Vol 585 ◽  
pp. 3-7 ◽  
Author(s):  
Anil Kumar Singh ◽  
Anandh Subramaniam
Keyword(s):  
Solid Solution ◽  
Regular Solution Model ◽  
Phase Segregation ◽  
Free Energy Calculations ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Equimolar Ratio ◽  
Two Phase ◽  
X Ray ◽  
High Entropy

In high entropy alloys (HEA) a disordered solid solution is entropically stabilized, in competition with possible intermediate compounds or phase segregation. It has been reported that disordered solid solutions are stabilized by the presence of five or more elements in the alloys; typically in an equimolar ratio. In the current investigation, the effect of Cu addition on the microstructure of CrFeNi alloy is rationalized by Gibbs free energy calculations. Two phase (both are FCC) solid solution are seen to form in CuCrFeNi alloy. The alloys are prepared by induction melting and are characterized by x-ray diffraction and scanning electron microscopy (in as-cast and annealed state). Enthalpies of mixing were calculated using Miedema's model and the regular solution model. Entropy of mixing is determined by using the Boltzmann's hypothesis.

Phase relationships in the Ce–Nd–B system at 773 K

2020 ◽  
Vol 111 (6) ◽  
pp. 526-532
Author(s):  
Xuehong Cui ◽  
Jinming Zhu ◽  
Ketong Luo ◽  
Jianlie Liang
Keyword(s):  
Solid Solution ◽  
Ternary System ◽  
Continuous Solid Solution ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Three Phase ◽  
Phase Relationships

Abstract Phase relationships in the Ce-Nd-B ternary system at 773 K were investigated by means of X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy techniques. Six borides, i. e. CeB4, CeB6, NdB4, NdB6, NdB66 and Nd2B5 are confirmed in this work. No ternary compound was observed. CeB4 and NdB4 were discovered to form the continuous solid solution phase (Ce,Nd)B4, CeB6 and NdB6 also form the solid solution phase (Ce,Nd)B6. The maximum solid solubility of Ce in (Ce,Nd)2B5 phase is 46.5 at.%. The isothermal section of the Ce-Nd-B ternary system at 773 K consists of 3 three-phase regions, 7 two-phase regions and 7 single- phase regions.

Experimental investigation on thermodynamic properties and crystal structure of La 0.78Ba0.22MnO3 compounds

2020 ◽  
Vol 34 (11) ◽  
pp. 2050101
Author(s):  
R. F. Hashimov ◽  
F. A. Mikailzade ◽  
S. V. Trukhanov ◽  
A. V. Trukhanov ◽  
D. M. Mirzayeva
Keyword(s):  
Crystal Structure ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermo Gravimetric ◽  
Two Phase ◽  
Cubic Symmetry ◽  
Space Group ◽  
Two Phases ◽  
Rhombohedral Symmetry

In this work, powder [Formula: see text] samples (purity of 99.99 % and density of [Formula: see text] were used. The crystal structure of [Formula: see text] compound was studied by X-ray diffraction method. It was determined that the crystal structure of this compound consists of two phases at room-temperature and under normal condition. These structure phases correspond to the cubic symmetry with Pm-3m space group and rhombohedral symmetry with the R-3c space group. Thermo Gravimetric (TG), Differential Scanning Calorimetry (DSC), Differential Thermo Gravimetric (DTG) and Differential Thermal Analysis (DTA) of [Formula: see text] compound were carried out in a high-temperature range of [Formula: see text]. It has been found that at high-temperatures, two-phase transition occurs in this compound. The value of thermodynamic parameters was found out for each phase transit.

scholarly journals Crystal structure of morimotoite from Ice River, Canada

2014 ◽  
Vol 29 (4) ◽  
pp. 325-330 ◽  
Author(s):  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Phase 1 ◽  
Site Occupancy ◽  
X Ray Diffraction ◽  
Alkaline Complex ◽  
Two Phase ◽  
Homogeneous Sample ◽  
Weight Percentage ◽  
Two Phases

The crystal structure of a morimotoite garnet, ideally Ca3(Ti4+Fe2+)Si3O12, from the Ice River alkaline complex, British Columbia, Canada was refined by the Rietveld method, space group $Ia\overline 3 d$, and monochromatic synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. Electron-microprobe analysis indicates a homogeneous sample with a formula {Ca2.91Mg0.05Mn2+0.03}Σ3[Ti1.09Fe3+0.46Fe2+0.37Mg0.08]Σ2(Si2.36Fe3+0.51Al0.14)Σ3O12. The HRPXRD data show a two-phase intergrowth. The reduced χ2 and overall R(F2) Rietveld refinement values are 1.572 and 0.0544, respectively. The weight percentage, unit-cell parameter (Å), distances (Å), and site occupancy factors (sofs) for phase-1 are as follows: 76.5(1)%, a = 12.156 98(1) Å, average <Ca–O> = 2.4383, Ti–O = 2.011(1), Si–O = 1.693(1) Å, Ca(sof) = 0.943(2), Ti(sof) = 0.966(2), and Si(sof) = 1.095(3). The corresponding values for phase-2 are 23.5(1)%, a = 12.160 67(2) Å, average <Ca–O> = 2.452, Ti–O = 1.988(3), Si–O = 1.704(3) Å, Ca(sof) = 1.063(7), Ti(sof) = 1.187(7), and Si(sof) = 1.220(8). The two phases cause strain that arises from structural mismatch and gives rise to low optical anisotropy. Because the two phases are structurally quite similar, a refinement using a single-phase model with anisotropic displacement parameters shows no unusual displacement ellipsoid for the O atom that requires a “split O-atom position”, as was done in previous studies.

Diffusion of Boron in Cobalt Sinters

2013 ◽  
Vol 58 (4) ◽  
pp. 1131-1136 ◽  
Author(s):  
J. Borowiecka-Jamrozek ◽  
J. Lachowski
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Mechanism ◽  
Reaction Diffusion ◽  
Optical Microscope ◽  
Process Time ◽  
Interatomic Potentials ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Calculation Results ◽  
Two Phases

Abstract The paper describes the process of diffusion taking place at the surface of sinters produced from Co Extrafine powder after saturation with boron. Boronizing was performed at a temperature of 950°C for 6 and 12 hours by applying B4C powder as a depositing source, NH4Cl + NaF as an activator and Al2O3 as an inert filler. The study involved determining the diffusion coefficient, which required analyzing the microstructure and thickness of the layers and the process time. The images obtained with a Leica DM-4000 optical microscope revealed a two-phase structure of the boride layers. The presence of the two phases, i.e. CoB and Co2B, was confirmed by X-ray diffraction (XRD). A model of diffusion of boron atoms into the cobalt substrate was developed assuming the reaction diffusion mechanism. This model was used to calculate the diffusion coefficient. It required taking account of the interatomic potentials of boron and cobalt. The calculation results were compared with the experimental data concerning the diffusion of boron in other materials.

Microstructure and Phase Transformation Temperatures of Two-Phase FeAl (B2) + FeAl2 Alloys

2014 ◽  
Vol 1760 ◽  
Author(s):  
Xiaolin Li ◽  
Martin Palm ◽  
Anke Scherf ◽  
Daniel Janda ◽  
Martin Heilmaier ◽  
...  
Keyword(s):  
Composition Dependence ◽  
Composition Range ◽  
Lamellar Microstructure ◽  
Lamellar Spacing ◽  
Al Alloys ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Creep Ductility ◽  
Heat Treated ◽  
Two Phases

ABSTRACTFe-Al alloys with about 55 to 65 at.% Al undergo a eutectoid transformation at 1095 °C: Fe5Al8 (ε) ↔ FeAl + FeAl2. Hence, as-cast Fe-Al alloys in this composition range show a very fine-scaled lamellar microstructure (average lamellar spacing below 500 nm) consisting of the two phases FeAl and FeAl2. The microstructure looks similar to the α2 + γ lamellar microstructure of Ti-Al-based alloys, which is known for having well-balanced properties in terms of creep, ductility and strength. However, there is limited knowledge about the properties of Fe-Al-based alloys in this composition range. In this study, a series of as-cast as well as heat-treated Fe-Al alloys with compositions between 57 and 63 at.% Al were investigated. The microstructures and crystal structures were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The composition dependence of all transition temperatures was obtained by differential thermal analysis (DTA).

Two-Phase Matrix of Ni3Al and γ- Ni Coatings Prepared by Laser Cladding

2011 ◽  
Vol 66-68 ◽  
pp. 2005-2009
Author(s):  
Guang Ping Cheng ◽  
Yi Zhu He
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Laser Cladding ◽  
Steel Substrate ◽  
Matrix Alloy ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Analysis Technique ◽  
Solid Solution Matrix ◽  
Increasing Temperature

As a solid solution matrix alloy, nickel-based alloys have the shortcomings that the strength will decrease with increasing temperature. The significance of this experiment is forming the two-phase matrix, in which γ- Ni solid solution are replaced partly by Ni3Al with potential performance at high temperature. In this paper, no visible cracks and pores Ni3Al/γ- Ni composite matrix coatings were prepared on mild steel substrate by laser cladding with mixed powders of two common thermal spying powders of Ni60AAA alloy and Ni-coated Al. The microstructure and phase constitution of the coating were studied through SEM, EDX and x-Ray diffraction analysis technique. The results show the composite coating consists of γ- Ni, Ni3Al, Cr23C6 and CrB, both the main matrix γ- Ni solid solution and the second matrix phase of Ni3Al being free uniformity dendrite and containing some alloying elements such as Fe, Cr, Si, etc,with the dendrites surrounded continuously by the eutectic. It may be possible for improving high-temperature performance.

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