Solid State Phase Equilibria Research Articles

Solid-State Phase Equilibria at 320°C of the Mg-Gd-Zn System in the Region of Less Than 50 at.% Gd

Solid-State Phase Equilibria at 320°C of the Mg-Gd-Zn System in the Region of Less Than 50 at.% Gd

Investigation in the ternary Ta-Ni-P system: Solid state phase equilibria at T=1070 K, crystal and electronic structures of new ternary phosphides

The solid state phase diagram for the ternary Ta-Ni-P system was established at T=1070 K in the region of up to 67 at% of P by means of X-ray powder diffraction methods (PXRD). Six ternary compounds, namely Ta4NiP (Nb4CoSi-type), Ta1.10–0.82Ni0.90–1.18P (TiNiSi-type), TaNiP2 (NbNiP2-type), Ta5.00–4.81Ni4.00–4.19P4 (Nb5Cu4Si4-type), TaNi2P (own structure type) and Ta1–0.08(1)Ni0.08(1)P2 (OsGe2-type) have been confirmed to exist. Rather minor Ta/Ni homogeneity ranges have been found for α-Ta3-xNixP (x=0.2) (Ті3Р-type), Ta1-xNixP (x=0.18) (NbAs-type), Ni3-xTaxP (x=0.2) (Ni3P-type) and Ni2-xTaxP (x=0.25) (Fe2P-type). The crystal structure of Ta4.811(9)Ni4.189(9)P4 has been refined from single crystal X-ray diffraction data (Nb5Cu4Si4-type, space group I4/m,a =9.8474(17), c=3.5182(7) Å, R1=0.0283, wR2=0.0470), while that of the new TaNi2P compound was determined by means of PXRD. This phosphide crystalizes in its own structure type (space group Pnma, a=8.3588(3), b=3.5208(1), c=6.7051(3) Å, RІ=0.044, RР=0.161). A new isostructural Fe-compound, TaFe2P (a=8.358(2), b=3.5194(7), c=6.703(1) Å), was also synthetized. The electronic structures of Ta5Ni4P4 and TaNi2P were analyzed using the tight-binding linear muffin-tin orbital (TB-LMTO) and extended Hückel methods.

Solid-state phase equilibria in the Er-Nd-Fe ternary system at 1073 K

The solid state phase equilibria in the ternary Er-Nd-Fe system at 1073 K in all the composition ranges were investigated using the experimental results of the X-ray powder diffraction analysis (XRD) as well as those obtained from the Scanning electron microscopy (SEM) equipped with Energy dispersive spectroscopy (EDS). The binary systems Er–Fe, Er–Nd and Nd-Fe were investigated prior to the study of the ternary one. Six binary compounds were identified to exist at this isothermal sectionss at 1073 K namely: ErFe2 (Fd3¯m-MgCu2 structure type), ErFe3 (R3¯m-PuNi3 structure type), Er6Fe23 (Fm-3m-Th6Mn23 structure type), Er2Fe17 (P63/mmc-Th2Ni17 structure type), Nd2Fe17 (R3¯m-Th2Zn17 structure type), and δ-NdEr (R3¯m-Sm structure type). No new ternary compounds were found in all investigated ternary alloy samples. The phase relations are governed by seven three-phase regions, sixteen two-phase regions and nine single-phase regions, as well as a small liquid area in the Nd-rich region. At 1073 K, we have observed that the highest solubility of Nd in ErFe2 is about 16.6 at. % Nd, while the Er1−xNdxFe3 solid solution based on binary ErFe3 extends up to 7.5 at. % Nd. The XRD and the SEM/EDS analyses show that there is no miscibility of Nd in Er6Fe23. The pair of the binary compounds Er2Fe17 and Nd2Fe17 extend through the ternary system parallel to the Nd-Er edge. The maximum homogeneity range of the Er2−xNdxFe17 solid solution reaches 5.3 at. % Nd, while that of the Nd2−xErxFe17 solid solution is about 1.6 at. % Er. In the Er-Nd binary system, the maximum solid solubility of Nd in Er is about 38.4 at. % Nd, and the solubility limit of Er in Nd is about 29.8 at. % Er.

Solid State Phase Equilibria of an Al⁻Sn⁻Y Ternary System.

A complete understanding of the solid-state phase equilibria of the ternary Al–Sn–Y system is essential for the development of both Al-based structural materials and Sn-based lead-free solders. In this work, the phase relationships in the Al–Sn–Y ternary system at 473 K were investigated mainly by means of X-ray powder diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) with energy disperse spectroscopy (EDS) analysis. The existence of 12 binary compounds, namely Sn3Y, Sn5Y2, Sn2Y, Sn10Y11, Sn4Y5, Sn3Y5, AlY2, Al3Y5, Al2Y3, AlY, Al2Y and α–Al3Y, was confirmed. Controversial phases (Sn5Y2 and Al3Y5) were found in this work. This isothermal section consisted of 15 single-phase regions, 27 two-phase regions and 13 three-phase regions. No ternary compounds were found and none of the other phases in this system revealed a remarkable solid solution at 473 K.

Solid State Phase Equilibria and Solid Solution of the Si-Y-Zr Ternary System at 1173 K

Insight into the phase equilibria, intermetallic compounds, solid solution and thermodynamic properties of the system of Zr, Si and rare earth elements is of academic interest for development of key structural materials in many fields. In this work, the solid state phase equilibria of the Si-Y-Zr ternary system at 1173 K were experimentally investigated by using x-ray powder diffraction and backscattered electron with energy dispersive x-ray analysis. The existence of 10 binary compounds namely, SiZr2, α-Si4Zr5, Si2Zr3, Si2Zr, α-SiZr, α-Si2Y, β-Si5Y3, SiY, Si4Y5 and Si3Y5, have been confirmed in this system at 1173 K, respectively. No binary compound was found in the Y-Zr binary system, and no ternary compound was found in current ternary system. The solid solubility of Y in the phases SiZr2, α-Si4Zr5, Si2Zr3, Si2Zr, α-SiZr, and Zr in α-Si2Y, β-Si5Y3, SiY, Si4Y5 and Si3Y5 was determined at 1173 K.

Phase equilibria of the Dy–Nb–Si ternary system at 1 273 K

Abstract The solid state phase equilibria in the Dy–Nb–Si ternary system at 1 273 K were experimentally determined by means of X-ray powder diffraction, differential scanning calorimetry and scanning electron microscopy equipped with energy dispersive X-ray analysis in the whole compositional range. The isothermal section of the Dy–Nb–Si ternary phase diagram contains 12 single-phase regions, 22 two-phase regions and 11 three-phase regions. At 1 273 K, the highest solubilities of Nb in β-DySi2, β-DySi1.67, Dy3Si4, β-DySi, Dy5Si4 and Dy5Si3 are extremely low (all less than 1 at.%). Whereas the maximum solubilities of Dy in NbSi2 and Nb5Si3 are approximately confirmed to be 1.12 at.% and 1.33 at.% Dy, respectively. Combining differential scanning calorimetry results with X-ray powder diffraction analysis, it is proved that the transformation temperatures of β-DySi1.67→α-DySi1.67 and Dy3Si4→β-DySi1.67 + β-DySi are 980 K and 1 480 K, respectively.

Experimental investigation of the Y-Fe-Ga ternary phase diagram: Phase equilibria and new isothermal section at 800 °C

The solid state phase equilibria in the Y-Fe-Ga ternary system at 800 °C were investigated by means of X-ray diffraction, scanning electron microscope (SEM) and quantitative electron probe microanalysis (EDS). The isothermal section of the Y-Fe-Ga ternary phase diagram contains 15 single phase-regions, 32 two phase-regions, 12 three phase-regions and one liquid area. The phase diagram at this temperature is characterized by the formation of ten binary stable phases. Among these, there are six extensions of the binary compounds Y2Fe17, YFe3, YFe2, YGa2, Y3Ga5 and Y5Ga3 into the ternary system Y2Fe17−x Gax (x≤2), YFe3−xGax (x≤0.8), YFe2−xGax (x≤0.14), YGa2−xFex (x≤0.5), Y3Ga5−xFex (x≤0.15) and Y5Ga3−xFex (x≤0.1), respectively. The homogeneity range of the YFe12−xGax ternary line compound is between (1.5≤x≤9.75).

Solid-State Phase Equilibria and Intermetallic Compounds of the Si-V-Zr Ternary System

Phase relations in the Si-V-Zr ternary system at 973 K (700 °C) were experimentally investigated using X-ray powder diffraction and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The isothermal section at 973 K (700 °C) is governed by seventeen three-phase regions, thirty-two two-phase regions, and sixteen single-phase regions. Ten binary compounds and one ternary compound (SiVZr) were confirmed. There are two new ternary compounds found in this work for the first time. One of them (Si4V3Zr2) was found in the stoichiometric composition around V 38 pct, Si 50 pct, and Zr 12 pct. The existence of another one (V17Si12Zr3) was observed while analyzing the XRD results of large quantities of equilibrated samples in the region around 54 at. pct V, 33 at. pct Si, and 13 at. pct Zr.

Interaction of tantalum, chromium, and phosphorus at 1070 K: Phase diagram and structural chemistry

Solid-state phase equilibria have been established in the Ta–Cr–P system in the region of 0–67at% P at 1070K through powder X-ray diffraction analysis. Mutual substitution of Ta and Cr in binary phosphides gives rise to significant homogeneity ranges in Ta1.00–0.66Cr0–0.34P (NbAs-type; a=3.332(3)–3.1366(3)Å, c=11.386(4)–11.364(2)Å), Ta3.0–2.1Cr0–0.9P (Ti3P-type, a=10.156(2)–9.9992(2)Å, c=5.015(1)–4.956(2)Å), and Cr3.0–2.4Ta0–0.6P (Ni3P-type, a=9.186(5)–9.217(4)Å, c=4.557(3)–4.5911(3)Å). A limited homogeneity range is found in the ternary phase Ta1.0–0.8Cr1.0–1.2P (TiNiSi-type, a=6.2344(5)–6.141(2)Å, b=3.5034(3)–3.3769(6)Å, c=7.3769(6)–7.357(2)Å). The OsGe2-type structures (space group C2/m) of a new P-rich compound, Ta0.92(2)Cr0.08(2)P2 (a=8.8586(3)Å, b=3.2670(2)Å, c=7.4871(2)Å, β=119.315(2)°) as well as of the Ti-containing analogue Ta0.93(3)Ti0.07(3)P2 (a=8.8592(5)Å, b=3.2663(3)Å, c=7.4870(5)Å, β=119.309(2)°) were refined from powder X-ray diffraction data.

ChemInform Abstract: Experimental Determination of the Equilibrium Relationship of Fe—Pd—Pr Ternary System at 773 K.

AbstractThe solid state phase equilibria in the title system are characterized by powder XRD, FESEM, DSC, and EDS.

Phase Equilibria in the Fe–Ho–Pt Ternary System at 1173 K

The solid-state phase equilibria in the Fe–Ho–Pt ternary system at 1173 K (Ho ≤75%) were investigated by x-ray diffraction, scanning electron microscopy, and energy-dispersive x-ray spectroscopy techniques. The 1173 K isothermal section consists of 18 single-phase regions, 33 two-phase regions, and 16 three-phase regions. At 1173 K, we observed that the maximum solid solubility of Pt in Fe17Ho2, Fe23Ho6, Fe3Ho, and Fe2Ho is below 1 at.%. The binary phase Fe5Ho was not observed. The maximum solubility of Ho in α-Fe is about 1 at.%, and it is below 1.5 at.% in γ-(Fe, Pt), FePt, FePt3, and (Pt, Fe) (the solid solution of Fe in Pt). The existence of HoPt5, HoPt3, HoPt2, Ho3Pt4, HoPt, Ho5Pt4, Ho5Pt3, Ho2Pt, and Ho3Pt is confirmed, and the maximum solid solubility of Fe in them is below 1 at.%.

Experimental determination of the equilibrium relationship of Fe–Pd–Pr ternary system at 773 K

The solid-state phase equilibria in the Fe–Pd–Pr ternary system at 773 K were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC) and energy dispersion spectroscopy (EDS) techniques. It is found that the 773 K isothermal section consists of 14 single-phase regions, 26 two-phase regions, 13 three-phase regions. At 773 K, it is observed that the highest solubility of Pr in FePd and FePd3 are 1.4 and 1.3 at.% Pr, respectively. The solid solubility of Fe in Pd5Pr, Pd3Pr, Pd2Pr, Pd3Pr2, Pd4Pr3, PdPr, Pd3Pr7, and that of Pd in Fe17Pr2 are very little and less than 1 at.%. In this work, at 773 K, the homogeneity ranges of phases FePd and FePd3 in the Fe–Pd binary system have been determined to be 49.6–61.1 at.% Pd for FePd and 62.54–80.55 at.% Pd for FePd3, respectively. A new ternary compound Pr6Fe13Pd with space group I4/mcm, a = 0.80900 (7) and c = 2.24401 (4) nm was discovered.

Phase equilibria of the Cu–Dy–Ti ternary system at 973 K

The solid-state phase equilibria of the copper (Cu)–dysprosium (Dy)–titanium (Ti) ternary system at 973 K has been experimentally investigated. The existence of nine binary compounds, Cu4Ti, Cu3Ti2, Cu4Ti3, CuTi, CuTi2, CuTi3, CuDy, Cu2Dy, and Cu5Dy was confirmed. The controversial phase of CuTi3 was found in this work. The temperature range of Cu7Dy was determined to be from 1112 to 1183 K. The phase relations at 973 K are governed by ten ternary phase regions, 21 binary phase regions, and 12 single-phase regions. The solid solubility of Cu in Dy is undetectable. None of the other phase in this system reveals a remarkable homogeneity range at 973 K.

Solid-State Phase Equilibria of the V-Si-Gd System at 973 K (700 °C)

The solid-state phase equilibria of the V-Si-Gd ternary system at 973 K (700 °C) were experimentally evaluated. The existence of nine binary compounds, namely, V3Si, V5Si3, V6Si5, VSi2, Gd5Si3, Gd5Si4, GdSi, GdSi1.67, and GdSi2−x, was confirmed, and no ternary compound was found at 973 K (700 °C). The homogeneity ranges of V3Si and GdSi2−x were investigated. It is worth mentioning that the Gd3Si4 compound was discovered through changing the experimental conditions, and its crystal structure was discussed.

Phase Equilibria at 1173 K in the Ternary Fe-Pt-Tb System

The solid-state phase equilibria in the ternary Fe-Pt-Tb system in the compositional region below 75 at.%Tb at 1173 K have been studied by using x-ray diffraction, scanning electron microscopy and energy dispersion spectroscopy techniques. The 1173 K isothermal section consists of 18 single-phase regions, 33 two-phase regions, and 16 three-phase regions. At 1173 K, the maximum solid solubility of Pt in α-(Fe, Tb) is less than 2 at.%Pt and that of Pt in Fe2Tb, Fe3Tb, Fe23Tb6, Fe17Tb2 is below 1 at.%Pt; the compounds Pt5Tb, Pt3Tb, Pt2Tb, Pt4Tb3, PtTb, Pt4Tb5, Pt3Tb5, PtTb2, and PtTb3 are confirmed to exist at 1173 K and the highest solid solubility of Fe in them is below 1 at.% Fe; the maximum solid solubility of Tb in α-(Fe, Pt), γ-(Fe, Pt), FePt, FePt3, and (Pt, Fe) (namely, the solid solution of Fe in Pt) is about 1, 2, 1.9, 1.5, and 1.5 at.%Tb, respectively. No ternary compound was found to exist in this section at 1173 K.

Constitution of the ternary system Cr–Ni–Ti

Abstract The nature of solid–liquid phase equilibria in the ternary system Cr–Ni–Ti was investigated using electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and differential thermal analysis. Literature data on solid state phase equilibria are confirmed. The Cr2Ti Laves phase modifications coexisting with Ni–Ti phases are clarified to be hexagonal C14-type and cubic C15-type. The C14-type Laves phase γCr2Ti is found to coexist with the liquid phase. It forms in the pseudobinary peritectic reaction pmax1 from L + β(Cr,Ti) at 1389 °C. On further cooling γCr2Ti + NiTi solidify at 1202 °C in the pseudobinary eutectic emax2. In the Cr-rich part of the system ternary eutectics occur at 1216 °C (E1: L = Ni3Ti + (Ni) + β(Cr,Ti)) and 1100 °C (E2: L = NiTi + Ni3Ti + β(Cr,Ti)), respectively. No ternary eutectic is found in the Ti-rich part. Rather the eutectic trough ends in the binary eutectic L = NiTi2 + β(Ti).

Solid-state phase equilibria in the Co–Pt–Ho ternary system at 1173 K

The solid-state phase equilibria in the Co–Pt–Ho ternary system at 1173K(Ho≤75%) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and energy dispersion spectroscopy (EDS) techniques. It is found that the 1173K isothermal section consists of 14 single-phase regions, 24 two-phase regions, and 12 three-phase regions. At 1173K, it is observed that the maximum solid solubility of Pt in Co17Ho2 is below 1at.% Pt, whereas in Co7Ho2, Co3Ho and Co2Ho it is about 1.5, 1 and 1.5at.% Pt, respectively. The maximum solubility of Ho in α-(Co, Pt) is below 1.5at.% Ho, and for Co it is below 1at.% Co in HoPt5, HoPt3, Ho3Pt4, HoPt, Ho5Pt4, Ho5Pt3, Ho2Pt and Ho3Pt with uniquely being about 18.5at.% Co in HoPt2. Co5Ho was not found at 1173K, and no new ternary compounds were observed.

Ternary compounds and solid-state phase equilibria in Mg-rich side of Mg-Zn-Ca system at 300 °C

The phase equilibria and compositions in Mg-rich side at 300 °C were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy, electron probe microanalysis, X-ray diffraction and transmission electron microscopy. The results show that two ternary compounds T 1 and T 2 can be in equilibrium with the Mg-based solid solution in Mg-Zn-Ca system. T 1 phase is a linear compound with the composition region (molar fraction) of 15% Ca, 20.5%-48.9% Zn and balanced Mg at 300 °C. Its hexagonal structure parameters decrease with increasing Zn content, i.e. a=0.992-0.945 nm, c=1.034-1.003 nm. T 2 phase has hexagonal structure with the composition region of 26.4%-28.4% Mg, 63.2%-65.5% Zn and 7.1%-8.4% Ca. At 300 °C, the solubility of Zn in the Mg-based solid solution increases for the addition of Ca, the maximum solubility of Zn is 3.7%. Three-phase fields consisting of α-Mg+Mg 2Ca+ T 1, α-Mg+ T 1+ T 2, α-Mg+ T 2+MgZn and MgZn+ T 2+Mg 2Zn 3 exist in the Mg-Zn-Ca system at 300 °C.

Solid-state phase equilibria and thermodynamic properties of ternary compounds in the Tl-Sb-S system

The Tl-Sb-S system has been studied in the composition region Tl2S-Sb2S3-S using differential thermal analysis, X-ray diffraction, and emf measurements on thallium concentration cells at temperatures from 300 to 390 K, and the 300-K isothermal section of its phase diagram has been mapped out. The existence of the ternary compounds TlSb5S8, TlSb3S5, TlSbS3, TlSbS2, Tl3SbS4, and Tl3SbS3 has been confirmed, and the position of the phase fields involving these compounds has been accurately determined. Using emf data, we have evaluated the partial molar functions (\(\Delta \bar G\) , \(\Delta \bar H\) , \(\Delta \bar S\) ) of the thallium in the alloys studied, the standard thermodynamic functions of formation of the ternary compounds, and their standard entropies.

Thermodynamic properties of phases in the Yb-Bi-Se system

The solid-state phase equilibria and thermodynamic properties of alloys in the Yb-Bi-Se system have been studied in the composition region YbSe-Bi2Se3-Se at temperatures from 300 to 400 K using emf measurements on concentration cells of the type $$ \left( - \right)YbSe\left( s \right)\left| {liquid electrolyte, Yb^{3 + } } \right|\left( {Yb - Bi - Se} \right)\left( s \right)\left( + \right). $$ The subsolidus phase diagram has been mapped out, and the partial thermodynamic functions of the YbSe pseudocomponent have been evaluated. Combining our data and the thermodynamic functions of YbSe and Bi2Se3, we have determined the partial thermodynamic functions of the ytterbium in the alloys and the integral thermodynamic functions of the ternary compounds YbBiSe3 (−ΔfG(298 K) = 496.0 ± 2.6 kJ/mol, −ΔfH(298 K) = 503.3 ± 4.3 kJ/mol, S0(298 K) = 214 ± 12 J/(mol K)), YbBi4Se7 (668.9 ± 8.7, 679.8 ± 9.0, 551 ± 14), and YbBi2Se4 (524.7 ± 4.6, 533.9 ± 5.7, 311 ± 11).