Si Ternary System Research Articles

Erratum to: The Co–Ga–Si ternary system at 870 K

Erratum to: The Co–Ga–Si ternary system at 870 K

The Co–Ga–Si ternary system at 870 K

The Co–Ga–Si ternary system at 870 K

First-principles calculations of phase stability in the Ti–Zr–Si ternary system

First-principles calculations of the enthalpies of formation of ternary compounds with Fe2P-type (C22, hP9, P6¯2m, N°189) and Mn5Si3-type (D88, hP16, P63/mcm, N°193) structures have been performed in the Ti–Zr–Si system. At low temperature, two ternary compounds C22- Ti3Zr3Si3 and D88-Ti4Zr6Si3 are stable. The existence at high temperature of two solid solutions, (TiZr)5Si3 with the Mn5Si3-type structure and (TiZr)2Si with the Fe2P-type structure, is emphasized. The calculated isothermal section at 1323 K agrees well with the experimental results in the Ti-rich region.

Anodic oxidation of alloys in the (α-Al–Mg2Si) quasibinary section of the Al–Mg–Si ternary system in 3% NaCl solution and principle of independence of electrochemical reactions

The paper studies the kinetics and mechanisms of anodic oxidation of aluminum alloys in the quasibinary section (α-Al–Mg2Si) of the Al–Mg–Si system in a 3% NaCl solution. According to the principle of independence of reactions, the electrochemical processes in two-phase alloys are shown to take place on each phase separately. On some areas of the surface, Al2O3 is formed as a reaction product, while α-SiO2 is formed on the other areas. It is established that the corrosion of the eutectic component occurs at the early oxidation stages, while α-Al dendrites are uniformly dissolved with a dominating transition of Mg2+ ions into the solution. The alloys that have the minimum amount of the eutectic component exhibit the highest corrosion resistance.

Experimental investigation of phase equilibria in the Ni–Co–Si ternary system

The phase equilibria of the Ni–Co–Si ternary system have been investigated by electron probe microanalyzer (EPMA) and X-ray diffraction (XRD) on the equilibrated alloys. Three isothermal sections of the Ni–Co–Si ternary system at 1000 °C, 1100 °C and 1200 °C were determined, and no ternary compound was found in this system. The obtained experimental results in the present work show that (1) there is a large α (Ni, Co) continuous solid solution; (2) the extensions of all the binary intermediate phases of the Ni–Si and Co–Si system into the ternary occur along the respective stoichiometric lines of fixed Si contents. The newly determined phase equilibria in this system will provide important support for the development of transition metal silicides and nickel based fillers.

Phase equilibria in the Fe–La–Si ternary system

The isothermal section of the phase diagrams at 1173, 1373 and 1573 K and vertical section phase diagrams in La(Fe 1− x Si x ) 13 (0.07≦ x≦0.40) and Fe 95Si 5–La 33.3Fe 33.3Si 33.3 (at. %) sections were experimentally determined mainly using X-ray diffractometer (XRD), electron probe microanalyzer (EPMA) and differential scanning calorimeter (DSC). The obtained phase diagrams showed that six ternary intermetallic compounds (IMCs), including the cubic NaZn 13-type La(Fe 1− x Si x ) 13 phase (τ 1) and the tetragonal Ce 2Ni 17Si 9-type La(Fe 1− x Si x ) 13 phase (τ 2), exist at temperatures over 1173 K at least and that most of the ternary phases, except the τ 1 and τ 2 phases, have only small solubility ranges from their stoichiometric compositions. It was also found that the τ 1 and τ 2 phases form by the following peritectic reactions: αFe (or L FeSi) + L La + LaFe 2Si 2 → τ 1 at about 1665 K and τ 1 + L FeSi + LaFe 2Si 2 → τ 2 at about 1623 K, respectively.

Thermodynamics and kinetics in liquid immiscible Cu–Cr–Si ternary system

This work firstly focuses on the thermodynamic and kinetic studies of the liquid phase separation in the Cu–Cr–Si ternary system. On the thermodynamic aspect, four isothermal sections of the Cu–Cr–Si system at 900 °C, 1000 °C, 1100 °C and 1200 °C have been experimentally determined by X-ray diffraction (XRD) and electron probe microanalyzer (EPMA) on the equilibrated alloys, and the phase equilibria in the Cu–Cr–Si ternary system has been thermodynamically assessed by using the CALPHAD ( Calculation of Phase Diagrams) technique on the basis of the presently obtained experimental results. The addition of Si can stabilize the metastable liquid phase separation in the Cu–Cr binary system, and increase its critical temperature. On the kinetic aspect, the formation of top–bottom and core–shell separated morphologies of the as-cast liquid immiscible Cu–Cr–Si alloys under various cooling rates have been detailedly analyzed.

Ternary Cr–Ga–Si system at 870 K

Using the results of X-ray phase, structural, and also metallographic analysis, we have constructed the isothermal section of constitution diagram of the Cr–Ga–Si ternary system at 870 K over the entire concentration range. Ternary compounds are not formed at the temperature of investigations. We have established the existence and determined precisely the homogeneity range of Cr 3 Si 1–x Ga x ( x = 0–0.357) substitution solid solution by the results of refinement of crystallographic parameters according to the Rietveld method [structural type Cr 3 Si , Pearson symbol cP8 , space group Pm[FORMULA]n , a = 4.556–4.5844(7) A, R B = 0.0353, R p = 0.009, R wp = 0.014, χ 2 = 3.68] and metallographic analysis.

Thermodynamic modeling of the Au–Sb–Si ternary system

Thermodynamic optimization of the Au–Sb binary system was updated as well as the Si–Sb binary system was assessed thermodynamically using the CALPHAD method based on the critical review of the available experimental information from the published literature. The solution phases including liquid, fcc_A1(Au), diamond_A4(Si) and rhombohedral_A7(Sb), are modeled as substitutional solutions and their excess Gibbs energies are expressed by a Redlich–Kister polynomial. The solubility of Si in the intermetallic compound AuSb 2 is not taken into account because of the lack of experimental information. Combined with previous assessment of the Au–Si binary system, thermodynamic modeling of the Au–Sb–Si ternary system was performed to reproduce well the measured phase equilibria. The liquidus projection and several vertical sections of this ternary system were calculated, which are in reasonable agreement with the reported experimental data.

Growing 3C-SiC heteroepitaxial layers on α-SiC substrate by vapour–liquid–solid mechanism from the Al–Ge–Si ternary system

In this work, we present and compare the results obtained from different Si-based melts (Ge–Si, Al–Si and Al–Ge–Si) for growing SiC layers on α-SiC substrate by vapour–liquid–solid (VLS) mechanism. It was found that, depending on melt composition, the deposit could be either a complete 3C or α-SiC layer or even a mixture of these polytypes. The binary Al–Si melt leads systematically to a highly p-type homoepitaxial α-SiC deposit while Ge–Si melt gives a non-intentional n-type doped layers of either 3C or 6H polytypes depending on growth conditions. However, highly p-type doped 3C heteroepitaxial deposit can be obtained if a small amount of Al is added to the Ge–Si binary liquid phase. This means that the VLS mechanism is very flexible and allows growing either n- or p-type SiC layers of 3C or 6H polytypes.

Experimental investigation of the Nd–Al–Si system

Abstract The isothermal section of the Nd–Al–Si ternary system at 500 °C has been investigated using differential thermal analysis, X-ray diffraction analysis, scanning electron microscopy and electron micro-probe analysis. Four ternary intermetallic compounds were confirmed: NdAl2Si2 (τ1), hP5-CaLa2O2 structure type, Nd2Al3Si (τ2), hP3-AlB2 structure type, NdAl1−xSi1+x, 0.25 ≤ x ≤ 0.3 (τ3), tI12-αThSi2 structure type and Nd2Al1−xSi1+x, 0 ≤ x ≤ 0.2, (τ5), oS8-CrB structure type. A new ternary intermetallic phase (τ4) was found: Nd4Al3Si3, orthorhombic oS20, isotypic with Pr4Al3Ge3.

Co–B–Si–Ta bulk metallic glasses designed using cluster line and alloying

The formations of Co-based Co–B–Si–Ta bulk metallic glasses, as well as their mechanical and corrosion properties have been explored in this work. The alloy compositions were designed by using the cluster line approach and the alloying strategy, where the cluster line referred to a straight composition line linking a specific binary cluster to the third element in a ternary alloy phase diagram. The base ternary compositions in the Co–B–Si ternary system were first determined by the intersection points of two cluster lines, Co–B cluster to Si and Co–Si cluster to B. Then these basic ternary compositions were a small amount of Ta alloyed to further improve the glass-forming abilities. Experimental results revealed that good glass formers with 4 mm in diameter occurred at Co 62.2B 26.9Si 6.9Ta 4, obtained by Ta alloying of the base intersection compositions of Co 7B 3–Si with Co 9Si–B. This bulk metallic glass have not only high thermal stabilities with high T g and T x values, but also exhibit high fracture strength of about 4760 MPa, high Vickers hardness of about 1460, a Young's modulus of 198 GPa, and good corrosion resistances in 1 mol/L HCl and 3 mass% NaCl solutions.

ChemInform Abstract: Isothermal Section of the Cu—Mn—Si Ternary System at 700 °C.

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Multi-phase Al-based ultrafine composite with multi-scale microstructure

A new class of Al-base multi-phase ultrafine composites with multi-scale microstructure, which exhibits high strength and large compressive plasticity at ambient temperature, has been developed in the Al–Cu–Si ternary system. The formation of the favorable multi-phase multi-modal structure can be achieved by proper alloy selection and by controlling the solidification process. The developed hierarchical ultrafine composites exhibit high fracture strength of ∼1 GPa and large compressive plasticity up to ∼25%. The large macroscopic plastic strain is attributed to the combination of dislocation-based slip deformation in the ductile phase and extensive shear banding in the intermetallic phase.

Experimental study of the 773 K isothermal section in the Ce–Ti–Si ternary system

The isothermal section at 773 K of the Ce–Ti–Si ternary system has been investigated by means of X-ray powder diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscope–energy dispersive X-ray spectroscopy (SEM–EDX). The existences of 11 binary compounds, namely Ce 5Si 3, Ce 3Si 2, Ce 5Si 4, CeSi, Ce 3Si 5, CeSi 2, Ti 3Si, Ti 5Si 3, Ti 5Si 4, TiSi and TiSi 2 have been confirmed. No ternary compound was found in this work. The results show that the phase equilibria consists of 14 single-phase regions, 25 binary phase regions and 12 ternary phase regions. The existence of the binary compound Ce 5Si 3 with the Cr 5B 3-type crystal structure (space group: I4/mcm, a = 0.7890, c = 1.373) was experimentally confirmed.

Isothermal section of the Gd–Zr–Si ternary system at 773 K

The isothermal section of the phase diagram of the Gd–Zr–Si ternary system at 773 K was investigated by X-ray powder diffraction, scanning electron microscope with energy dispersive analysis, metallographic analysis and differential thermal analysis techniques. The experimental results show that the isothermal section consists of 13 single-phase regions, 23 two-phase regions and 11 three-phase regions. Ten binary compounds, i.e., Zr 2Si, Zr 3Si 2, Zr 5Si 4, ZrSi, ZrSi 2, α-GdSi 2− x , GdSi 1.67, GdSi, Gd 5Si 4, and Gd 5Si 3 in the Gd–Zr–Si system were confirmed to exist at 773 K. The maximum solubility of Gd in GdSi 2 is about 2.8 at.% Gd. No ternary compound is formed in this system at 773 K.

Isothermal section of the Cu–Mn–Si ternary system at 700 °C

Abstract Isothermal section of the Cu–Mn–Si ternary system at 700 °C was investigated over the whole concentration range by means of X-ray diffraction, scanning electron microscopy equipped with energy dispersive X-ray analysis, and electron probe microanalysis. A new MgZn2-type ternary compound T with an average composition of Cu50.8Mn36.3Si12.9 (in at.%) was observed, while two ternary compounds with approximate formulae of Cu32.5Mn50.2Si17.3 and Cu28.3Mn60.5Si11.2 reported in the literature were not found. The lattice parameters of the T phase were determined to be a = b = 4.83(6) and c = 7.846(7) A. The binary compound Mn5Si2, the existence of which is controversial in the literature, was observed at 700 °C. Five three-phase equilibria, Mn3Si + T + (Cu), Mn5Si3 + Mn5Si2 + T, Mn5Si3 + MnSi + γ-Cu56Si11, MnSi + Mn11Si19 + η-Cu19Si6, and Mn11Si19 + η-Cu19Si6 + (Si) were well determined. The solubilities of Cu in (βMn), Mn6Si, Mn9Si2, Mn3Si, Mn5Si2, Mn5Si3, MnSi and Mn11Si19 were determined to be 0.6, 0.8, 2.1, 1.5, 2.3, 2.5, 1.6 and 0.8 at.% Cu, respectively. The solubilities of Mn in γ-Cu56Si11 and η-Cu19Si6 were measured to be about 3.7 and 2.7 at.% Mn, respectively.

Thermodynamic assessment of La–Si and Mg–La–Si systems

Based on available phase equilibria and thermodynamic data, thermodynamic assessment has been carried out for La–Si binary system using CALPHAD approach. A set of self-consistent thermodynamic model parameters was obtained. The solution phases including Liquid, BCC, FCC, DHCP and Diamond_A4 were modeled as substitutional phases, of which the excess Gibbs energies being formulated with the Redlich–Kister polynomial function. And six intermediate compounds were treated as stoichiometric phases. Incorporated with thermodynamic parameters of Mg–La and Mg–Si binary systems cited from literatures, an isothermal section at 773 K of Mg–La–Si ternary system was thermodynamically optimized, including four ternary stoichiometric compounds (τ 2 , τ 3 , τ 4 and τ 5 ) and one semi-stoichiometric compound (τ 1 ). The calculated phase equilibria and thermodynamic properties agreed well with experimental data.

Thermodynamic description of Ru–Ge–Si ternary system

With the help of Miedema's method, Ru–Ge–Si ternary system has been thermodynamically described through the CALPHAD approach. Firstly, mixing enthalpy of liquid Ru–Ge alloy was calculated in light of Miedema's empirical method. Subsequently, the Ru–Ge and Ru–Si binary systems were thermodynamically assessed. Solution phases including Liquid, Hcp and Diamond were described with a substitutional model, of which the excess Gibbs energies were formulated with the Redlich–Kister polynomial. Binary intermetallic phases were treated as stoichiometric compounds. Then, combined with the reported parameters of Ge–Si system, phase equilibria in the ternary Ru–Ge–Si system were assessed where the ternary solubility in intermetallic compounds was taken into consideration. In addition, liquidus projection was further calculated.

The isothermal section of the Pr–Ti–Si ternary system at 773 K

The isothermal section of the Pr–Ti–Si ternary phase diagram at 773 K was investigated by powder X-ray diffraction (XRD) and differential thermal analysis (DTA). The binary compound Pr 3Si 4 is not observed at 773 K. There are nine binary compounds in this system, which are Ti 3Si, Ti 5Si 3, Ti 5Si 4, TiSi, TiSi 2, Pr 5Si 3, Pr 5Si 4, PrSi and PrSi 2. No ternary compounds were found in this work. The 773 K isothermal section of this ternary system consists of 12 single-phase regions, 21 two-phase regions and 10 three-phase regions. The compound Ti 5Si 3 has a homogeneity range extending from about 37 to 38 at.% Si. The existence of solid solubility of the other phases was not observed.