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1.
A simple method to estimate the surface tensions of binary alloys has been developed by assuming that the partial molar excess
free energies are proportional to the number of nearest neighbors in both the bulk solution and in the surface itself. In
order to estimate the surface tension of the alloys, excess free energies of the alloys and the surface tensions of the pure
components are required. This method has been applied to ten alloys exhibiting positive, positive as well as negative, and
negative deviations from ideal solution behavior. The method depends upon the reliability of the thermodynamic data for the
bulk solutions, and, further, it is important to use an interpolation scheme that is consistent with the Gibbs-Duhem requirement,
when the thermodynamic data are presented in tabular form as a function of composition. To accomplish this interpolation,
a special calculation technique is presented. 相似文献
2.
M. E. Fraser W. K. Lu A. E. Hamielec R. Murarka 《Metallurgical and Materials Transactions B》1971,2(3):817-823
A novel experimental technique for the measurement of surface tension of molten metals has been developed. It is based on
the Rayleigh equation which relates frequency and surface tension for an oscillating drop. A systematic study has shown this
equation to be valid for a liquid metal droplet levitated electromagnetically in an inert flowing gas with no prior calibration
required. It is, therefore, an absolute method. The frequencies of oscillation of droplets of pure iron and nickel in a 6
pct H2-He gas mixture were measured by high speed cinematography. Surface tensions were obtained for temperatures of 1550° to 1780°C
for iron and 1475° to 1650°C for nickel.
M. E. FRAZER, Formerly Graduate Student, Department of Metallurgy and Materials Science, McMaster University, Hamilton, Ontario,
Canada. 相似文献
3.
Iron-nickel alloys with 8 and 16 wt pct nickel and iron-chromium-nickel alloys with 8 pct nickel and chromium contents in
the range of 2 to 22 pct were equilibrated with iron and nickel in flowing CH4-H2 gas mixtures and in sealed capsules under partial vacuum at temperatures between 700 and 1060°C. Carbon activities in these
alloys were established from the carbon concentrations in the nickel by applying Henry’s law to the solubility of carbon in
nickel that was determined in the temperature range of 500 to 1000°C. First-order free-energy interaction parameters were
used to relate the carbon activities to composition and temperature in the single-phase austenitic Fe-Ni and Fe-Cr-Ni alloys.
An expression was also developed to evaluate carbon activities in Fe-Cr-Ni alloys in the region of higher chromium contents
(〉4 wt pct) that result in a two-phase austenite plus carbide mixture at these temperatures. 相似文献
4.
The rate of deposition of iron, nickel and iron-nickel layers from carbonyl vapors is shown to be controlled by diffusion
across the gas phase boundary layer in contact with the heated substrate. At a constant flow rate the rate of deposition is
shown to increase with increase in temperature up to a critical value above which the rate of deposition either remains constant
(for high flow rates) or decreases (for low flow rates). This behavior is explained in terms of the thermal convection contribution
to mass transfer in the reaction system. It is shown that the composition of alloy films produced from carbonyl mixtures at
temperatures greater than 200°C (473 K) can be predicted to be approximately equal to the molar ratios of iron and nickel
in the vapor phase when the carbonyls alone constitute the vapor phase. These predictions cannot be extended to situations
where high dilution of the carbonyls in another gas is used, or to deposition temperatures of less than 200°C (473 K). 相似文献
5.
D. W. G. White 《Metallurgical and Materials Transactions B》1971,2(11):3067-3071
The surface tensions of 99.9999 pct Pb and Sn and of alloys made from lead and tin of the same purity have been measured by
the sessile-drop method. The surface tension of lead was determined from the melting point, the surface tension of tin from
200°C (32°C of supercooling) and the surface tensions of the Pb−Sn alloys from the respective liquidus temperatures, all,
up to a temperature of about 560°C. Within the limits of experimental error, data for both pure metals plot in a rectilinear
fashion with negative slopes, thus: γlead=472.7−0.085t(±5) dyne/cm γtin=569.0−0.080t((±5) dyne/cm The surface tensions of Pb−Sn alloys are not straight-line functions of temperature and the evidence indicates
that the temperature coefficients of surface tension are slightly positive at the liquidus temperature. 相似文献
6.
Usually gas solubility measurements in metals are done isothermally and separately for the solid and liquid states. The knowledge of gas solubility at phase changes, especially in the melting range, is of a predominant interest e.g. for foundrymen or for welders, as defects (segregation, gas pores, inclusions) may occur due to the change of solubility. Therefore, a method has been developed, in which a finely grained sample is exposed to a temperature gradient in a long ceramic tube, until equilibrium with the gas phase with regard to local temperature is reached in all locations. The chilled sample is subdivided into small samples which can be analysed for gas content. The method is demonstrated for the determination of nitrogen solubility in iron and some iron-nickel alloys, where results for the austenite and δ-ferrite phases are presented. 相似文献
7.
8.
The enthalpies of formation of liquid binary (Cu+Fe, Co, Ni) alloys are studied by direct reaction calorimetry in the whole
range of compositions at 1873, 1823, and 1753 K, respectively. The integral molar enthalpies of mixing are found to be positive
in all three systems with the maximum values approaching 10.8±0.7 kJ/mol−1 at x
Fe=0.43, 7.1±0.9 kJ/mol−1 at x
Co=0.55, and 3.7±0.5 kJ/mol−1 at x
N1=0.53. Partial molar enthalpies at infinite dilution constitute 59.4±3.3 kJ/mol−1 for iron, 44.3±4.1 kJ/mol−1 for cobalt, and 14.9±2.2 kJ/mol−1 for nickel in liquid copper. Similar values for copper in liquid iron, cobalt, and nickel are 36.6±3.9, 45.3±6.0, and 17.7±4.4
kJ/mol−1, respectively. The results are compared with the thermodynamic data available in literature and discussed in connection to
the equilibrium-phase diagrams. In particular, decreasing from Cu-Fe to Cu-Ni liquid alloys positive values of the excess
thermodynamic functions of mixing are fully in accord with the growing stability of phases in these systems. The excess entropies
of mixing are estimated by combining the established enthalpies with carefully selected literature data for the excess Gibbs
functions. Analysis of possible contributions to the enthalpies of mixing indicates that the experimentally established regularity
in ΔH values along the 3d series is likely to arise from the difference in d-band width and d-electron binding energy of the alloy constituents. 相似文献
9.
The solubility of nitrogen in liquid iron-base Fe-Ni-Al alloys has been measured up to the solubility limit for formation
of aluminum nitride using the Sieverts’ method. Measurements were conducted over the temperature range from 1843 to 2023 K
and aluminum concentration range from 1.5 to 3.0 wt pct Al. The effect of nickel additions was determined at 2, 5 and 10 wt
pct Ni. The cross interaction parameter describing the effect of nickel and aluminum on the activity coefficient of nitrogen
in iron was determined. The first and second order effects of nickel on the activity coefficient of aluminum also were determined.
The solubility product of aluminum nitride increases with increasing aluminum content and increasing temperature. Addition
of nickel decreases the solubility products of aluminum nitride in lower aluminum content alloys. However, the effect of the
cross interaction terme
Al
NiAl becomes significant with increasing aluminum content and compensates for the effects of the first and second order nickel-nitrogen
and nickelaluminum interaction terms. Therefore the effect of nickel additions show little effect on the solubility products
of aluminum nitride in higher aluminum alloys. 相似文献
10.
11.
Rates of absorption of hydrogen in stagnant liquid iron and ten (Fe-X) binary iron alloy systems were studied by an unsteady-state gas-liquid metal diffusion cell technique. These rates were
found to be controlled by diffusion of hydrogen in the liquid phase. Chemical diffusion coefficients (D
h) were measured in pure iron and Fe-X alloys in the following (at. pct) composition ranges: Mn (0 to 5), Cr (0 to 25), V (0 to 25), Nb (0 to 10), Mo (0 to 25),
W (0 to 5), Ni (0 to 75), Co (0 to 75), Sn (0 to 10), and Cu (0 to 25). All measuredD
H values at 1600°C lie between 7 × 10-4 and 16 × 10-4 sq cm per sec. The diffusion coefficients found for pure iron can be represented by DH
Fe = 4.37 × 10−3 exp (−4134 ± 1012)/RT cm2/sec where the uncertainty in the activation energy, Q, in cal per mole, corresponds to the 90 pct confidence level. A linear
relationship was found between the logarithm of the hydrogen diffusion coefficient DH
Fe-X and the interaction parameter εH
X for low and medium concentrations of alloying elementX, when applied to a fixed concentration ofX(5 or 25 at. pct) and to individual periods in the periodic table. A useful linear correlation also appears to exist between
logDH
Fe-X and hydrogen solubility for fixed concentration ofX and with respect to the period in whichX is found.
Formerly Research Assistant, Department of Mineral Engineering, Stanford University, Stanford, Calif.
This paper is based upon a thesis submitted by P. J. DEPUYDT in partial fulfillment of the requirements of the degree of Doctor
of Philosophy at Stanford University and part of a presentation made at the 1970 Annual AIME Meeting. 相似文献
12.
13.
Summary A study was made of the effect of composition on the surface tension of nickel-silicon alloys with up to 50 at.% Si. An inflection was observed on the isotherm at 28 at.% Si. The unusual shape of the surface tension versus composition curve is ascribed to a microheterogeneous structure of the melt and the presence in the latter of short-range order. 相似文献
14.
15.
16.
KATAOKA Yoshiyukki FURUSA WA Eiichi KOHNO Hisayuki ARAI Tomoya MARTIN Al INOUE Hisashi MANTLER Michael 《冶金分析》2009,29(5):6-11
用基本参数法分析了镍、钴和铁基合金,对每种元素在整个含量范围内用单一校准进行了测定,并获得了满意的结果。研究显示,本方法可以采用多通道光谱仪对主次元素进行分析测定。例如,对镍元素来说,在质量分数0%到100%的浓度范围内,准确度达到质量分数0.14%。我们还发现,在铬的分析中,三级激发很显著,对整体强度的贡献率达到2.4%。通过将三级激发考虑进理论强度计算,方法的准确度可由质量分数0.14%提高到0.10%。对灵敏度进行了最小二乘拟合法校准,研究显示二次拟合多项式用单一校准曲线在整个浓度范围内都能给出很好的结果。在多通道光谱仪中,当通道不再适合谱线重叠时,理论强度重叠校正法是有效的手段。 相似文献
17.
The solubility of hydrogen in liquid pure iron and in several liquid binary iron alloys at steelmaking temperatures has been
determined by measuring changes in hydrogen pressure in a constant volume system. The solubility of hydrogen corrected to
one atmosphere pressure was found to be 27.70 ± 1.28 cc (STP)/100 grams in liquid pure iron at 1600°C with a temperature coefficient
of solubility of 2.9 x 10-2 cc (STP)/°C. This solubility decreases with increasing concentrations of aluminum, boron, or silicon; slightly increases
with increasing concentrations of chromium, nickel, and niobium; and is almost independent of the concentrations of copper
or sulfur. The data are compared with those of previous investigators who employed the more conventional Sieverts’ or sampling
techniques. 相似文献
18.
H. A. Davies 《Metallurgical and Materials Transactions B》1972,3(11):2917-2921
The density and surface tension of five liquid Na-ln alloys, containing between 0.5 and 7 at. pct In, have been measured in
the temperature range 170° to 400°C using a maximum bubble pressure technique which incorporates an automatic pressure measuring
and recording device. The results are compared with corresponding data reported previously for Na-Cd alloys. The gram-atomic
volumes of the Na-ln alloys, calculated from the densities, indicate a substantial contraction on alloying which is, on average,
about double that for the Na-Cd alloys and qualitatively consistent with thermodynamic data for the two systems.
The surface tension of liquid sodium is increased slightly on adding indium, indicating a lower indium concentration in the
surface than in the bulk, in contrast to the marked surface active behavior of cadmium. The surface excess concentrations
of indium and cadmium are calculated using Gibbs’ adsorption equation. The surface excess entropy, estimated from the temperature
dependence of the surface tension, is compared and briefly discussed for the two systems. 相似文献
19.
Padday’s cone technique allows determination of the surface tension of a liquid from measurement of the maximum excess force
exerted on a cone during its immersion in, or withdrawal from, the liquid and knowledge of the density of the liquid. As the
technique does not require rupture of the meniscus, an equilibrium measurement is obtained. The surface tensions of Fe-saturated
iron silicate melts and Fe-saturated calcium ferrites, measured at 1410 °C using iron cones, are in good agreement with values
in the literature obtained using the hollow cylinder technique. The maximum excess forces exerted on Pt-Rh cones immersed
in liquid iron oxides at 1460 °C in the composition range from saturation with iron toX
Fe2O3 = 0.205 have been measured. The surface tensions of these melts cannot be determined unambiguously from the experimental
measurements because of an uncertainty in the densities of the melts. However, it is shown that the literature values for
the surface tension of liquid iron oxide are incorrect because of an error in the experimental procedures used. 相似文献
20.
《Acta Metallurgica》1987,35(8):2071-2079
Hydrogen embrittlement of amorphous alloys based on iron and nickel was examined in constant extension rate tests during cathodic polarization. Tests were carried out at a current density of 50 A·m−2 in 0.1 M H2SO4 with and without addition of NaAsO2 and NaCl. Hydrogen permeation and polarization curves were measured. Differences in the degree of hydrogen embrittlement were ascribed mainly to differences in the entry of hydrogen into the alloys. It was suggested that a low degree of embrittlement resulted largely from a hindrance of hydrogen entry. For alloys containing phosphorus, this might be associated with phosphorus-containing oxyanions and salts. For the alloy with higher silicon content it may be associated with the formation of oxides of silicon. 相似文献