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1.
The phase diagram of the (Sb2Te3)100?x –InSb x system was determined based on x-ray diffraction (XRD) analysis, differential thermal analysis (DTA), and microhardness and density measurements. An intermediate compound with composition Sb2Te3·2InSb was formed as a result of syntectic reaction, melting incongruently at 553 °C. This compound has tetragonal lattice with unit cell parameters of a = 4.3937 Å, b = 4.2035 Å, c = 3.5433 Å, α = 93.354°, and β = γ = 90°. Sb2Te3·(2 + δ)InSb (?1 ≤ δ ≤ +1) and (Sb2Te3)100?x (InSb) x (90 ≤ x ≤ 100) solid solutions exist in the investigated system, based on the intermediate compound Sb2Te3·2InSb and on InSb, respectively. Also, two invariant equilibria exist in the system, with eutectic point coordinates at compositions of x = 60 and x ≈ 85 mol% InSb and eutectic temperatures of T E = 541 and T E ≈ 501 °C, respectively.  相似文献   

2.
The binary bismuth-rhodium (Bi-Rh) phase diagram was reinvestigated from 23 to 60 at.% Rh with focus on the BiRh phase, applying powder-x-ray diffraction (XRD), high temperature powder-XRD, differential thermal analyses and scanning electron microscopy. The phase boundaries of the BiRh phase at 750 °C and the temperature of its peritectic decomposition were refined. In addition, the existence of the two phases Bi4Rh and Bi2Rh (in two modifications depending on temperature) could be confirmed. Most of the reaction temperatures reported in the literature could be verified within a range of about ± 10 °C. Nevertheless, a few temperatures had to be revised, such as those of the peritectic reactions L + Rh \(\rightleftharpoons\) BiRh at 979 °C and L + BiRh \(\rightleftharpoons\) β-Bi2Rh at 785 °C. No evidence could be found for the presence of a stable Bi3Rh phase in well annealed samples; from the present results it must be concluded that Bi3Rh is actually metastable. On the other hand, a new orthorhombic phase BiRh0.81 was discovered which crystallizes in the MnP structure type (Pmna). It was found that the temperatures of the transition between the low-temperature modification α-Bi2Rh and its high-temperature form β-Bi2Rh depend considerably on the presence or absence of metastable Bi3Rh and stable BiRh0.81, respectively.  相似文献   

3.
The phase equilibria in the Cu-Sn-Sb ternary system were investigated by means of electron-probe microanalysis and x-ray diffraction. Firstly, ternary solubilities of η-Cu6Sn5, δ-Cu41Sn11, Cu11Sb3, ε-Cu3Sb and η-Cu2Sb, were less than 7 at.% Sb or Sn at 400 °C. Besides, an re-stabilized ternary solubility, Cu6(Sn,Sb)5, was detected with a homogeneity range of Cu: 52.9-53.3 at.%, Sn: 28.4-30.9 at.%, and Sb: 15.8-18.7 at.%. Its origin was traced back to high-temperature stabilization of the binary η-Cu6Sn5 phase. Thirdly, the metastable phase, Cu11Sb3, was observed at 400 °C in the Cu-Sn-Sb ternary system; On raising the temperature to 500 °C, the ε-Cu3Sn phase still retained a large solubility for Sb, at?~?16 at.%, while the ε-Cu3Sb was replaced by β-Cu3Sb with a dual-cornered large homogeneity range. Similarly, a ternary homogeneity range of Cu: 83.8-84.9 at.%, Sn: 2.6-6.2 at.%, and Sb: 9-12.5 at.%, was found and deduced to be the high temperature stabilization phase of γ-Cu11(Sb,Sn)2 at 500 °C.  相似文献   

4.
Phase relationships in the Al-Mn-Dy ternary system at 500 °C have been investigated by X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, and electron probe microanalysis. From the experimental results it was concluded that the isothermal section consists of 16 single-phase regions, 26 two-phase regions and 12 three-phase regions. Two extensive solid solutions, (Al x Mn1?x )12Dy and (Al1?x Mn x )2Dy, were observed. The solid solution (Al x Mn1?x )12Dy forms by Al replacing Mn in Mn12Dy, while the continuous solid solution (Al1?x Mn x )2Dy forms by Mn and Al mutually substituting in Al2Dy and Mn2Dy, respectively. The maximum solid solubility of Al in Mn12Dy is 79.3 at.%.  相似文献   

5.
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 Zn4+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.  相似文献   

6.
The aim of this work is to correlate the pitting potential (Epit) evolution with the kinetics of σ phase precipitation in the 2205 duplex stainless steel aged at 850 °C after solution treatment at 1150 °C. The potentiodynamic polarization curves indicate a reduction of the pitting corrosion resistance with the aging time, which is revealed by a decrease in the Epit values from 0.65 to 0.40 VSCE. Thus, Epit values are used to determine the kinetics parameters of the σ phase precipitation. The experimental transformed fraction agrees well with the one calculated by using the modified Kolmogorov–Johnson–Mehl–Avrami equation with an impingement parameter c?=?0.6.  相似文献   

7.
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.  相似文献   

8.
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.  相似文献   

9.
La0.7Sr0.3Mn1?x Ni x O3 (x = 0, 0.025, 0.050 and 0.075) ceramics were prepared by the conventional solid-state reaction method. The partial substitution of Mn by Ni2+ leads to a decrease in cell volume as well as a structural transition from the rhombohedral to the orthorhombic structure. Ni2+ doping increases the electrical resistivity, decreases the semiconductor–metal transition temperature (T ms) and relatively enhances the room temperature magnetoresistance (MR), especially in x = 0.025 and around T ms. With respect to conduction mechanism, the small polaron hopping (SPH) and the variable range hopping (VRH) models were used to examine conduction in the semiconducting region.  相似文献   

10.
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 ErAg1?xSn2+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 Er25.4Ag23.4Sn51.2, Er25.7Ag23.0Sn51.3, Er25.7Ag21.7Sn52.6, Er25.2Ag18.6Sn56.2 (at.%) respectively). Melting point of the phase Er25.7Ag21.7Sn52.6 (at.%) was determined to be 1199 K by differential thermal analysis.  相似文献   

11.
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 (Ti40Cu36?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 Cu8Zr3, CuTiZr, and Pd3Zr were mainly identified in the proportions dependent on the alloy compositions.  相似文献   

12.
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.  相似文献   

13.
The Ti-Pb diagram was investigated in the region 0 to 58 pet Pb and from 500°C to liquidus temperatures. Three reactions were encountered: 1—β→α+Ti4Pb at 725±10°C; 2—β+L→Ti4Pb at 1305±10°C; and 3—the possible eutectic L→Ti4Pb and γ between 1200° and 1300°C.  相似文献   

14.
A tailor-made thermodynamic database of the Fe-Mn-Al-C system was developed using the CALPHAD approach. The database enables predicting phase equilibria and thereby assessing the resulting microstructures of Fe-Mn-Al-C alloys. Available information on the martensite start (Ms) temperature was reviewed. By employing the Ms property model in the Thermo-Calc software together with the new thermodynamic database and experimental Ms temperatures, a set of model parameters for the Fe-Mn-Al-C system in the Ms model was optimised. Employing the newly evaluated parameters, the calculated Ms temperatures of the alloys in the Fe-Mn-Al-C system were compared with the available measured Ms temperatures. Predictions of Ms temperatures were performed for the alloys, Fe-10, 15 and 20 wt.% Mn-xAl-yC. The predictability of the Ms model can be further validated when new experimental Ms temperatures of the Fe-Mn-Al-C system are available.  相似文献   

15.
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 (Co0.5-1.5Mo1.5-0.5Zr, 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.  相似文献   

16.
The characteristics of microwave power absorption in materials for ferrous metallurgy, including iron oxides (Fe2O3, Fe3O4 and Fe0.925O) and bitumite, were explored by evaluating their dielectric loss (Q E) and/or magnetic loss (Q H) distributions in the 0.05-m-thick slabs of the corresponding materials exposed to 1.2-kW and 2.45-GHz microwave radiation at temperatures below 1100°C. It is revealed that the dielectric loss contributes primarily to the power absorption in Fe2O3, Fe0.925O and the bitumite at all of the examined temperatures. Their Q E values at room temperature and slab surface are 9.1311 × 103 W m?3, 23.7025 × 103 W m?3, and 49.5999 × 103 W m?3, respectively, showing that the materials have the following heating rate initially under microwave irradiation: bitumite > Fe0.925O > Fe2O3. Compared with the other materials, Fe3O4 has much stronger power absorption, primarily originated from its magnetic loss (e.g., Q H = 1.0615 × 106 W m?3, Q H/Q E = 2.4185 at 24°C and slab surface), below its Curie point, above which the magnetic susceptibility approaches to zero, thereby causing a very small Q H value at even the surface (Q H = 1.0416 × 105 W m?3 at 880°C). It is also demonstrated that inhomogeneous power distributions occur in all the slabs and become more pronounced with increasing temperature mainly due to rapid increase in permittivity. Characterizing power absorption in the oxides and the coal is expected to offer a strategic guide for improving use of microwave energy in ferrous metallurgy.  相似文献   

17.
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.  相似文献   

18.
A series of FeCo-based thin films were prepared by magnetron sputtering without applying an induced magnetic field.The microstructure,electrical properties,magnetic properties and thermal stability of FeCo,FeCoSiN monolayer thin film and[FeCoSiN/SiN_x]_n multilayer thin film were investigated systematically.When FeCo thin film was doped with Si and N,the resistivity and soft magnetic properties of the obtained FeCoSiN thin film can be improved effectively.The coercivity(H_c),resistivity(ρ) and ferromagnetic resonance frequency(f_r) can be further optimized for the[FeCoSiN/SiN_x]_n multilayer thin film.When the thickness of FeCoSiN layer and SiN_x layer is maintained at 7 and 2 nm,the H_c,p and f_r for[FeCoSiN/SiN_x]_n multilayer thin film are 225 A·m~(-1)392 μΩ·cm~(-1) and 4.29 GHz,respectively.In addition,the low coercivity of easy axis(H_(ce) ≈ 506 A·m~(-1)) of[FeCoSiN/SiN_x]_n multilayer thin film can be maintained after annealing at 300 ℃ in air for 2 h.  相似文献   

19.
In this work, the microstructure and mechanical properties of rapidly solidified Ti50?x/2Ni50?x/2Hf x (x = 0, 2, 4, 6, 8, 10, and 12 at.%) and Ti50?y/2Ni50?y/2Si y (y = 1, 2, 3, 5, 7, and 10 at.%) shape memory alloys (SMAs) were investigated. The sequence of the phase formation and transformations in dependence on the chemical composition is established. Rapidly solidified Ti-Ni-Hf or Ti-Ni-Si SMAs are found to show relatively high yield strength and large ductility for specific Hf or Si concentrations, which is due to the gradual disappearance of the phase transformation from austenite to twinned martensite and the predominance of the phase transformation from twinned martensite to detwinned martensite during deformation as well as to the refinement of dendrites and the precipitation of brittle intermetallic compounds.  相似文献   

20.
Fe-Ni-based metal amorphous nanocomposites with a range of compositions (Fe100?x Ni x )80Nb4Si2B14 (30 ≤ x ≤ 70) are investigated for motor and transformer applications, where it is beneficial to have tunable permeability. It is shown that strain annealing offers an effective method for tuning permeability in these alloys. For an Fe-rich alloy, permeability increased from 4000 to 16,000 with a positive magnetostriction. In a Ni-rich alloy, permeability decreased from 290 to 40 with a negative magnetostriction. Significant elongations (above 60%) are observed during strain annealing at high stress. Crystallization products have been determined in all alloys heated to 480°C. γ-FeNi is formed in all alloys, while (Fe30Ni70)80Nb4Si2B14 also undergoes secondary crystallization at temperatures of approximately 480°C to form a phase with the Cr23C6-type structure and a likely composition of Fe21Nb2B6. Toroidal losses have been measured for (Fe70Ni30)80Nb4Si y B16?y (0 ≤ y ≤ 3) at various annealing temperatures. At an induction of 1 T and frequency of 400 Hz and 1 kHz, the toroidal losses obtained are W1.0T, 400 Hz = 0.9 W/kg and W1.0T, 1 kHz = 2.3 W/kg, respectively. These losses are lower than losses recently reported for state of the art 3.0% and 6.5% silicon steels, a Metglas Fe-based amorphous alloy, and some Fe-based nanocomposites.  相似文献   

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