Phase Field Modeling of Joint Formation During Isothermal Solidification in 3DIC Micro Packaging

In this paper, a computational multi-phase field approach is utilized to study the formation of the Cu/Sn/Cu micro-joint in 3-Dimensional Integrated Circuits (3DICs). The method considers the evolution of the system during isothermal solidification at 250 °C for the case of two different interlayer thicknesses (5 and 10 µm). The Cu/Sn/Cu interconnection structure is important for the micro packaging in the 3DIC systems. The thermodynamics and kinetics of growth of η-Cu₆Sn₅ and ?-Cu₃Sn interfacial intermetallics (IMCs) are investigated by coupling the multi-phase field method with CALPHAD approach. The interaction of the phases is addressed by assuming a metastable condition for the Cu/Sn reacting system. The simulations start with the nucleation and rapid growth of the η-Cu₆Sn₅ IMCs at the initial stage, the nucleation and growth of ?-Cu₃Sn IMCs at the intermediate stage ending with the full consumption of Sn layer and the domination of ?-Cu₃Sn IMCs at the later stages. In addition, comparing different diffusion rates through the grain boundary of η phases show that their morphology is the direct consequence of balance of kinetic forces. This work provides a valuable understanding of the dominant mechanisms for mass transport in the Cu/Sn/Cu low volume interconnections. The results show that the phase field modeling is successful in addressing the morphological evolution and growth of IMC layers in the 3DIC joint formation.     

Composition dependences of thermodynamical properties associated with Pb-free ternary,quaternary, and quinary solder systems

In the present study, Chou’s General Solution Model (GSM) has been used to predict the enthalpy and partial enthalpies of mixing of the liquid Ag–In–Sn ternary, Ag–In–Sn–Zn quaternary, and Ag–Au–In–Sn–Zn quinary systems. These are of technical importance to optimize lead-free solder alloys, in selected cross-sections: x_In/x_Sn = 0.5/0.5 (ternary), Au–In_0.1–Sn_0.8–Zn_0.1, Ag–In_0.1–Sn_0.8–Zn_0.1 (quaternary), and t = x_Au/x_In = 1, x_In = x_Sn = x_Zn (quinary) at 1173, 773, and 773 K, respectively. Moreover, the activity of In content in the ternary alloy system Ag–In–Sn has been calculated and its result is compared with that determined from the experiment, while the activities of Ag contents associated with the alloys mentioned above have been calculated. The other traditional models such as of Colinet, Kohler, Muggianu, Toop, and Hillert are also included in calculations. Comparing those calculated from the proposed GSM with those determined from experimental measurements, it is seen that this model becomes considerably realistic in computerization for estimating thermodynamic properties in multicomponent systems.     

Properties of the Ti<Subscript>40</Subscript>Zr<Subscript>10</Subscript>Cu<Subscript>36</Subscript>Pd<Subscript>14</Subscript> BMG Modified by Sn and Nb Additions

The results of investigation of the influence of additions of 2 and 3 at.% of Sn and simultaneously of Sn and 3 at.% Nb on microstructure and properties of the bulk metallic glasses of composition (Ti₄₀Cu_36?x Zr₁₀Pd₁₄Sn _x )_100?y Nb _y are reported. It was found that the additions of Sn increased the temperatures of glass transition (T _g), primary crystallization (T _x ), melting, and liquidus as well as supercooled liquid range (ΔT) and glass forming ability (GFA). The nanohardness and elastic modulus decreased in alloys with 2 and 3 at.% Sn additions, revealing similar values. The 3 at.% Nb addition to the Sn-containing amorphous phase decreased as well all the T _g, T _x , T _L, and T _m temperatures as ΔT and GFA; however, relatively larger values of this parameters in alloys containing larger Sn content were preserved. In difference to the previously published results, in the case of the amorphous alloys containing small Nb and Sn additions, a noticeable amount of the quenched-in crystalline phases was not confirmed, at least of the micrometric sizes. In the case of the alloys containing Sn or both Sn and Nb, two slightly different amorphous phase compositions were detected, suggesting separation in the liquid phase. Phase composition of the alloys determined after amorphous phase crystallization was similar for all compositions. The phases Cu₈Zr_3, CuTiZr, and Pd₃Zr were mainly identified in the proportions dependent on the alloy compositions.     

Isothermal Section of Er-Ag-Sn System at 873 K

The isothermal section of the Er-Ag-Sn system at 873 K was constructed with the use of scanning electron microscopy, energy-dispersive x-ray microanalysis and x-ray powder diffraction. Two ternary compounds were confirmed at this temperature: ErAgSn (LiGaGe structure type, P6₃mc, Z = 2, a = 4.6595(2) Å, c = 7.2872(3) Å) and non-stoichiometric phase ErAg_1?xSn_2+x (Cu₃Au structure type, Pm-3m, Z = 1). For the last one homogeneity range was established (0.08 < x < 0.24) and lattice parameters were determined (a = 4.5007(4), 4.5040(2), 4.5107(1), 4.5412(1) Å for the compositions Er_25.4Ag_23.4Sn_51.2, Er_25.7Ag_23.0Sn_51.3, Er_25.7Ag_21.7Sn_52.6, Er_25.2Ag_18.6Sn_56.2 (at.%) respectively). Melting point of the phase Er_25.7Ag_21.7Sn_52.6 (at.%) was determined to be 1199 K by differential thermal analysis.     

Influence of Nb on microstructure and mechanical properties of Ti-Sn ultrafine eutectic alloy

In this study, A series of the high strength (T₈₂Sn₁₈)_100-xNb_x (x=0, 1, 3, 5, and 9 at%) ultrafine eutectic alloys with large plasticity are developed by suction casting method. The Ti₈₂Sn₁₈ binary eutectic alloy consists of a mixture of a hcp Ti₃Sn and a α-Ti phases having the plate-like lamellar type duplex structure with micro scaled eutectic colony. From the (T₈₂Sn₁₈)₉₇Nb₃, the alloy display structural heterogeneous distribution of ultrafine-scaled phases composed of β-Ti(Nb) solid solution surrounded by alternating plate-like shaped Ti₃Sn and α-Ti phases. With increasing Nb content, the volume fraction of β-Ti is continuously increased, which induced improving mechanical properties both strength and plasticity. Especially, (Ti₈₂Sn₁₈)₉₁Nb₉ alloy has the outstanding combination of the high strength (σ _y ≈1.1 GPa) and large plasticity (ε _p ≈36%) at room temperature.     

Experimental Investigation of the Isothermal Section of the Fe-Mn-Sn System at 723 K

Phase relationships in the Fe-Mn-Sn ternary system at 723 K were investigated using equilibrated approach. More than 40 alloys were prepared by arc-melting method and examined by x-ray powder diffraction, scanning electron microscopy and energy dispersive spectroscopic. The existence of five binary compounds FeSn, FeSn₂, MnSn₂, Mn₃Sn₂, Mn₃Sn and one intermediate solid solution γ(Fe, Mn) have been confirmed in this system. FeSn₂ and MnSn₂ form continuous solid solution (Fe_1?x, Mn _x )Sn₂ (0 ≤ X ≤ 1) and the lattice parameters of (Fe, Mn)Sn₂ reduced linearly with increasing of Fe content. At 723 K, the maximum solid solubilities of Fe in αMn, βMn, Mn₃Sn, Mn₃Sn₂ phases and Mn in FeSn, αFe are about 25, 34.8, 37.3, 46.2 at.% Fe and 26.8, 5.5 at.% Mn respectively. The solid solubilities of γ(Fe, Mn) ranged from 42.1 to 78.1 at.% Fe and the limited solubility of Sn is around 3 at.%. The isothermal section consists of 6 three-phase regions, 13 two-phase regions and 9 single-phase regions. No ternary compound was found at 723 K in this system.     

Phase Equilibria of the Ternary Al-Cu-Zn Alloys on Al-Zn Rich Side

Phase equilibria of the Al-Cu-Zn system on Al-Zn rich side was experimentally determined with 16 alloys annealed at 360 °C. The annealed alloys were examined by means of x-ray diffraction, electron probe microanalysis and differential scanning calorimetry. Five single-phase regions and seven two-phase regions as well as three three-phase regions, i.e. α-(Al)?+?θ-Al₂Cu?+?τ′-Al₄Cu₃Zn, α-(Al)?+?τ′-Al₄Cu₃Zn?+?ε-CuZn₄ and α-(Al)?+?ε-CuZn₄?+?(Zn), were determined. The partial isothermal section of the Al-Cu-Zn system on Al-Zn rich side at 360 °C was constructed based on the obtained experimental data in this work. It was observed that the solid solution phase α-(Al) would easily decompose into ε-CuZn₄, (Zn) and α′-(Al) at the ambient temperature in the early stages. The ternary phase τ′-Al₄Cu₃Zn would form and ε-CuZn₄ would disappear gradually along with the extension of aging time.     

Synthesis and Structural Characterization of Sb-Doped TiFe<Subscript>2</Subscript>Sn Heusler Compounds

Ternary Heusler compounds form a numerous class of intermetallics, which include two families with general compositions ABC and AB₂C, usually referred to as half- and full-Heusler compounds, respectively. Given their tunable electronic properties, made possible by adjusting the chemical composition, these materials are currently considered for the possible use in sustainable technologies such as solar energy and thermoelectric conversion. According to theoretical predictions, Sb substitution in the TiFe₂Sn full-Heusler compound is thought to yield band structure modifications that should enhance the thermoelectric power factor. In this work, we tested the phase stability and the structural and microstructural properties of such heavily doped compounds. We synthesized polycrystalline TiFe₂Sn_1?xSb_x samples, with x?=?0, 0.1, 0.2 and 1.0 by arc melting, followed by an annealing treatment. The structural characterization, performed by x-ray powder diffraction and microscopy analyses, confirmed the formation of the pseudo-ternary Heusler structure (cF16, Fm-3m, prototype: MnCu₂Al) in all samples, with only few percent amounts of secondary phases and only slight deviations from nominal stoichiometry. With increasing Sb substitution, we found a steady decrease in the lattice parameter, confirming that the replacement takes place at the Sn site. Quite unusually, the as-cast samples exhibited a higher lattice contraction than the annealed ones. The fully substituted x?=?1.0 compound, again adopting the MnCu₂Al structure, does not form as stoichiometric phase and turned out to be strongly Fe deficient. The physical behavior at room temperature indicated that annealing with increasing temperature is beneficial for electrical and thermoelectrical transport. Moreover, we measured a slight improvement in electrical and thermoelectrical properties in the x?=?0.1 sample and a suppression in the x?=?0.2 sample, as compared to the undoped x?=?0 sample.     

Experimental Determination of the Phase Equilibria of the La-Zn-Si System at 600 °C

The isothermal section at 600 °C of the La-Zn-Si system was established by using equilibrated alloys and the diffusion couple technique. Microstructural observation and phase identification were performed using optical microscopy, scanning electron microscopy with energy dispersive x-ray spectroscopy and a wave dispersive x-ray spectrometer, and x-ray powder diffraction. Seven ternary compounds were identified in this ternary system, and temporally designated as τ ₁, τ ₂, τ ₃, τ ₄, τ ₅, τ ₆ and τ ₇. Two previously reported ternary compounds, viz. τ ₁ and τ ₂, were found to exist at 600 °C. EDS analysis revealed that the τ ₁ phase contained Si from 2.4 to 6.1 at.% and La from 22.3 to 23.3 at.%. The compositional region of the τ ₂ single-phase ranged from 28.3 to 40.7 at.% for Si and from 31.5 to 33.1 at.% for La. Two new ternary phases, τ ₅ and τ ₆, were identified. The τ ₅ phase with the CeNiSi₂-type was determined to have a composition range of 36.9-39.2 at.% Si for about 24 at.% La. The τ ₆ phase with the ThCr₂Si₂-type was found to have a composition range of 18.9-19.7 at.% La and 27.4-30.6 at.% Si. The crystal structures of τ ₃, τ ₄, and τ ₇ were not determined. The solubility of Si in LaZn₁₃, LaZn₁₁, La₂Zn₁₇, La₃Zn₂₂, and LaZn₅ was negligible, and that of Si in LaZn₄, LaZn₂ and Zn in LaSi₂, La₃Si₂ was determined as 5.1, 2.3, 16.2 and 3.8 at.%, respectively.     

Phase Equilibria of the Co-Mo-Zr Ternary System at 1000 °C

The isothermal section of the Co-Mo-Zr ternary system at 1000 °C was investigated by using 29 alloys. The annealed alloys were examined by means of x-ray diffraction, optical microscopy, and electron probe microanalysis. It was confirmed that three ternary phases, λ₁ (Co_0.5-1.5Mo_1.5-0.5Zr, hP12-MgZn₂), ω (CoMoZr₄) and κ (CoMo₄Zr₉, hP28-Hf₉Mo₄B), exist in the Co-Mo-Zr ternary system at 1000 °C. And the experimental results also indicated that there are sixteen three-phase regions at 1000 °C. Thirteen of them were well determined in the present work: (1) (γCo)?+?Co₁₁Zr₂?+?Co₂₃Zr₆, (2) (γCo)?+?Co₂₃Zr₆?+?ε-Co₃Mo, (3) Co₂₃Zr₆?+?ε-Co₃Mo?+?μ-Co₇Mo₆, (4) (Mo)?+?μ-Co₇Mo₆?+?Co₂Zr, (5) (Mo)?+?Co₂Zr?+?λ₁, (6) (Mo)?+?Mo₂Zr?+?λ₁, (7) λ₁?+?Mo₂Zr?+?CoZr, (8) Co₂Zr?+?CoZr?+?λ₁, (9) Mo₂Zr?+?CoZr₂?+?ω, (10) κ?+?Mo₂Zr?+?ω, (11) CoZr₂?+?liquid?+?ω, (12) (βZr)?+?liquid?+?ω and (13) (βZr)?+?κ?+?ω. The homogeneity of λ₁ spans in the range of 28.66-50.77 at.% Co and 15.71-37.03 at.% Mo, and that for ω is within the range of 18.66-23.64 at.% Co and 8.53-14.68 at.% Mo. The homogeneity range for κ is from 8.09 at.% to 9.94 at.% Co and 23.13 at.% to 25.58 at.% Mo. The maximum solubility of Zr in μ-Co₇Mo₆ phase, Mo in Co₂Zr phase and Co in Mo₂Zr phase were determined to be 6.17, 11.27 and 9.14 at.%, respectively. While the solubility of Zr in ε-Co₃Mo and (γCo) phases, Mo in Co₁₁Zr₂ and CoZr phases were detected to be extremely small. According to this work, the Co₂₃Zr₆ phase contained 15.61 at.% Mo and 12.7 at.% Zr. In addition, the maximum solubility of Co and Zr in (Mo) phase and Mo in (γCo) phase were measured to be 3.50, 5.44 and 7.40 at.%, respectively.     

Experimental Investigation of the Binary Mn-Sb Phase Diagram

The binary manganese-antimony (Mn-Sb) phase diagram was reinvestigated in the whole composition range using powder-XRD, DTA and SEM-EDX. The phase boundaries and melting temperatures of the ferromagnetic phases MnSb and Mn₂Sb were modified by taking into account the new experimental data. Most of the reaction temperatures could be verified within a range of ±10 °C. Nevertheless, a few temperatures had to be revised, such as the eutectic reaction L → β-Mn + Mn ₂ Sb at 893 °C and the eutectoid reaction β-Mn → α-Mn + Mn ₂ Sb at 718 °C. The previously reported peritectic melting behavior of MnSb could be confirmed. The variation of the lattice parameters of the NiAs-(B8 ₁ ) type MnSb phase with composition was determined. A revised version of the of the Mn-Sb phase diagram is presented.     

Experimental Investigation and Thermodynamic Calculation of the Phase Equilibria in the Co-Cu-V Ternary System

The phase equilibria of the Co-Cu-V ternary system at 900, 1000, 1100 and 1200 °C have been experimentally determined by optical microscopy and electron probe micro-analysis of the equilibrated alloys. The phase transformations were investigated by means of the differential scanning calorimetry. Based on the experimental data of phase equilibria and thermodynamic properties, the thermodynamic assessment of the Co-Cu-V ternary system was carried out by using the calculation of phase diagrams method. A consistent set of the thermodynamic parameters leading to reasonable agreement between the calculated results and experimental data was obtained in the Co-Cu-V ternary system. Meanwhile, the calculated results show that the critical temperature of metastable magnetically induced miscibility gap of (α _f Co) and (α _p Co) phases in the Co-V system gradually decreases with increasing Cu composition in the range of 0-3 wt.% additions.     

Microstructure,Phase Occurrence,and Corrosion Behavior of As-Solidified and As-Annealed Al-Pd Alloys

In the present work, we studied the microstructure, phase constitution, and corrosion performance of Al₈₈Pd₁₂, Al₇₇Pd₂₃, Al₇₂Pd₂₈, and Al₆₇Pd₃₃ alloys (metal concentrations are given in at.%). The alloys were prepared by repeated arc melting of Al and Pd granules in argon atmosphere. The as-solidified samples were further annealed at 700 °C for 500 h. The microstructure and phase constitution of the as-solidified and as-annealed alloys were studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction. The alloys were found to consist of (Al), ε _n (~ Al₃Pd), and δ (Al₃Pd₂) in various fractions. The corrosion testing of the alloys was performed in aqueous NaCl (0.6 M) using a standard 3-electrode cell monitored by potentiostat. The corrosion current densities and corrosion potentials were determined by Tafel extrapolation. The corrosion potentials of the alloys were found between ? 763 and ? 841 mV versus Ag/AgCl. An active alloy dissolution has been observed, and it has been found that (Al) was excavated, whereas Al in ε _n was de-alloyed. The effects of bulk chemical composition, phase occurrence and microstructure on the corrosion behavior are evaluated. The local nobilities of ε _n and δ are discussed. Finally, the conclusions about the alloy’s corrosion resistance in saline solutions are provided.     

Influence of Interdiffusion in Sn Solution on Growth of Cu<Subscript>3</Subscript>Sn and Cu<Subscript>6</Subscript>Sn<Subscript>5</Subscript> Formed in Semi-infinite and Finite Cu-Sn Diffusion Couples

Reactive diffusion in the Cu-Sn binary system has been studied by using pure Cu/electrically plated Sn with 0.1-0.2 mm thicknesses diffusion couples (EP-couples) at 473 K. The interdiffusion coefficients, \(\tilde{D}\), of the Cu₃Sn and Cu₆Sn₅ diffusion phase layers were determined at the center of these layers by supposing linear concentration (\(C_{\text{i}}\))-distance (X) curves in these layers and by neglecting the interdiffusion in the Sn terminal solution (IDS) as the previous researchers have neglected it. By using \(\tilde{D}\) thus determined, the phase boundary concentrations for the layers obtained in this work and these parameters for the Cu terminal solution chosen appropriately, \(C_{\text{i}}\)-X curves were determined numerically for various values of interdiffusion coefficient, \(\tilde{D}_{\text{in Sn}}\), and the solubility limit of Cu mole fractions, \(N_{\text{Cu}}^{\text{in Sn}}\), in the Sn terminal solution by our method reported previously taking the molar volume change effect into account. The \(C_{\text{i}}\)-X curves obtained experimentally could be reproduced numerically well by neglecting IDS. This result, on the other hand, suggests a large influence of IDS in the semi-infinite diffusion couples (S-couples) or the diffusion couples used by the previous researchers. The quantitative evaluation of the influence in S-couples revealed that it makes the widths of the diffusion layers thinner than those in the present EP-couples in which the influence on the widths is negligibly small. The evaluation of the influence in the diffusion couples used by the previous researchers indicates larger values of \(N_{\text{Cu}}^{\text{in Sn}}\) than those reported as the value of the equilibrium phase diagram.     

Electrical Conductivity and Dielectric Permittivity of γ-Irradiated Nanocomposites Based on Ultrahigh-Molecular-Weight Polyethylene Filled with α-SiO<Subscript>2</Subscript>

UHMWPE/SiO₂ composites were obtained from a homogeneous mixture of ultrahigh-molecular- weight polyethylene (UHMWPE) and silicon dioxide (α-SiO₂) by hot pressing. The temperature dependence (20–170°C) of their conductivities σdс prior to and after γ irradiation (D = 200 kGy), the effect of absorbed dose on the σ_dс value (dose dependence), the behavior of the function logσ_dc = f(T) under heating–cooling conditions, and the frequency dependences (25–106 Hz) of the real (ε') and imaginary (ε'') parts of the complex dielectric constant were studied. The logσ_dc = f(T) dependence was shown to have in both cases a complex pattern: “breaks” due to phase transitions were observed. With an increase in the concentration of α-SiO₂, the ε' and ε'' (tanδ) values in the matrix increased and the frequency dependences of these values corresponded to an exponential rule.     

Preparation and Thermoelectric Properties of Sn-Based Type VIII Single-Crystalline Clathrate Via a-Sn Flux Method

In this study, type VIII Ba₈Ga₁₆Sn₃₀ single-crystal clathrates with different stoichiometric ratios were prepared using the a-Sn self-flux method. The structures of the samples were also investigated. Results indicate that n-/p-type single-crystal clathrates can be obtained by adjusting the initial content of Ga. Samples were determined to be n-type when the initial Ga content was X = 12, 13, and 14; and p-type when X = 16 and 18. The samples exhibited high melting points and large lattice parameters, as well as increasing Ga content. The electrical conductivities of the samples were lower than those prepared using the Sn self-flux method because of the low carrier concentration. The elemental composition of the sample was near the theoretical value when the Ga content was X = 14 and 16, which also yielded the highest Seebeck values of ?523 μV/K and 331 V/K, respectively. Finally, the sample with X = 14 and 18 exhibited the highest ZT values of 0.82 and 0.46, respectively, at a temperature of 480 K in n-/p-type.     

Electrical Transport Properties of Single-Crystalline β-Zn<Subscript>4</Subscript>Sb<Subscript>3</Subscript> Prepared Through the Zn-Sn Mixed-Flux Method

β-Zn₄Sb₃ is a promising p-type thermoelectric material for utilization in moderate temperatures. This study prepares a group of single-crystalline β-Zn₄Sb₃ samples using the Zn-Sn mixed-flux method based on the stoichiometric ratios of Zn_4+x Sb₃Sn _y . The effect of Zn-to-Sn proportion in the flux on the structure and electrical transport properties is investigated. All samples are strip-shaped single crystals of different sizes. The actual Zn content of the present samples is improved (>3.9) compared with that of the samples prepared through the Sn flux method. Larger lattice parameters are also obtained. The carrier concentration of all the samples is in the order of over 10¹⁹ cm^?3. With increasing Sn rate in the flux, this carrier concentration decreases, whereas mobility is significantly enhanced. The electrical conductivity and Seebeck coefficients of all the samples exhibit a behavior that of a degenerate semiconductor transport. Electrical conductivity initially increases and then decreases as the Sn ratio in the flux increases. The electrical conductivity of the x:y = 5:1 sample reaches 6.45 × 10⁴ S m^?1 at 300 K. Benefitting from the electrical conductivity and Seebeck coefficient, the flux proportion of the x:y = 7:1 sample finally achieves the highest power factor value of 1.4 × 10^?3 W m^?1 K^?2 at 598 K.     

Movement of Multiple Markers in Cu/Zn Multiple Phase Diffusion Couples and Its Numerical Analysis

Movement of multiple markers (M-Ms) embedded in the Cu end member of a Cu/Zn multiple phases diffusion couple (M-couple) has been experimentally investigated at 623 K and the alignment of the M-Ms after diffusion anneal was reproduced by the numerical analysis that the authors have previously reported. Two intermediate phases, γ and ?, were found in the Cu/Zn M-couple. The M-Ms bent toward Zn side at Cu/γ phase interface and show almost a linear line in the γ phase. They again bent at γ/? interface toward Zn side. The Kirkendall marker position, X _k, locates in the ? phase layer. From this result, ratio, R = D _Zn/D _Cu, of the intrinsic diffusion coefficients with respect to the mole fixed frame of reference was determined to be about 46 at X _k. On the assumption of a constant value of R = 46 in the ? phase and appropriate constant values of R = 10-1000 in the γ phase, alignments of M-Ms after diffusion anneal were numerically reproduced. By fitting the alignment of M-Ms obtained numerically on the experimental result, the value R in γ phase is estimated to be very large value of 500.     

Isothermal Sections of Pd-Cu-Sn System at 500 and 800 °C

The isothermal sections of the Pd-Cu-Sn system at 500 and 800 °C up to 50% Sn were constructed. Two ternary phases τ and (Pd,Cu)₃Sn of tetragonal and orthorhombic syngony respectively were discovered in the palladium-rich region. At both temperatures, solubility of tin in the FCC solid solution phase (α) has a pronounced minimum around 75-85 at.% Cu. γ-Pd_2?x Sn and η-Cu₆Sn₅ phases of Ni₂In type form a continuous (Pd,Cu)_2?x Sn phase.     

450 °C and 600 °C Isothermal Sections of the Zn-Cr-Si Ternary Phase Diagram

The 450 and 600 °C isothermal sections of the Zn-Cr-Si system were experimentally constructed using scanning electron microscopy equipped with energy dispersive x-ray spectrometry, and x-ray diffraction. Six three-phase regions in the 450 °C section and five three-phase regions in the 600 °C section were identified experimentally. No ternary compound was found. Si has low solubility in CrZn₁₇. The Zn solubility in CrSi₂, Cr₅Si₃, and Cr₃Si are all less than 2.2 at.%. The CrSi phase cannot be in equilibrium with the η-Zn phase. Thermodynamic extrapolation of the Zn-Cr-Si system was carried out and showed good agreement with experimentally determined phase relationships.