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1.
Tomohito Shimpo Takeshi Yoshikawa Kazuki Morita 《Metallurgical and Materials Transactions B》2004,35(2):277-284
The interaction between calcium and phosphorus in molten silicon was investigated for predicting the removal of phosphorus
from silicon by an acid leaching treatment with calcium addition. In the present study, two immiscible liquids of silicon
and lead were equilibrated, and the interaction parameter between calcium and phosphorus and the self-interaction parameter
of phosphorus in molten silicon at 1723 K were determined.
In the derivation process, the following activity coefficients and the interaction parameters of metallic impurities in molten
silicon and lead at 1723 K were also obtained:
The effect of the calcium addition to silicon improves the subsequent removal of phosphorus in the acid leaching treatment,
and the increase in removal fraction of phosphorus was observed remarkably with the addition of calcium in silicon. 相似文献
2.
Boron removal by titanium addition in solidification refining of silicon with Si-Al melt 总被引:4,自引:0,他引:4
Takeshi Yoshikawa Kentaro Arimura Kazuki Morita 《Metallurgical and Materials Transactions B》2005,36(6):837-842
In order to effectively remove B from Si for its use in solar cells, a process involving B removal by solidification refining
of Si using a Si-Al melt with Ti addition was investigated. For clarifying the effect of Ti addition on B removal from the
Si-Al melt, TiB2 solubilities in Si-64.6 at. pct Al melt at 1173 K and Si-60.0 at. pct Al melt at 1273 K were determined by measuring the
equilibrium concentrations of B and Ti in the presence of TiB2 precipitates. The small solubilities of TiB2 in the Si-Al melt indicate the effective removal of B from the Si-Al melt by Ti addition. Further, solidification experiments
of Si-Al alloys containing B by Ti addition were performed, and the effect of Ti addition on the solidification refining of
Si with the Si-Al melt was successfully confirmed. 相似文献
3.
The dissolution equilibrium of calcium vapor in liquid iron was carried out at 1873 K in a two-temperature zone furnace using
a vapor-liquid equilibration method. A sealed Mo reaction chamber and a self-made CaO crucible were used in this study. The
thermodynamic parameters obtained are as follows.
For reaction Ca (g)=[Ca],
The relation between dissolved calcium in liquid iron and calcium vapor can be expressed as
The interaction parameters of third elements on calcium determined at 1873 K are as follows:
相似文献
4.
Hideki Ono-Nakazato Kenji Taguchi Tateo Usui Keishi Tamura Yuuji Tomatsu 《Metallurgical and Materials Transactions B》2001,32(6):1113-1118
The standard Gibbs energies of formation of Cr2N and CrN have been measured by an equilibration technique and by using thermogravimetry and differential thermal analysis
(TG-DTA) at temperatures ranging from 1232 to 1523 K. The results are expressed as follows:
The standard Gibbs energies of formation of Cr2N and CrN determined by the present work are more negative than the values in the JANAF Tables by about 14 and 5 kJ/mol, respectively,
in the measured temperature range. 相似文献
5.
Victor T. Witusiewicz Ferdinand Sommer 《Metallurgical and Materials Transactions B》2000,31(2):277-284
The partial (Δ
and the integral (ΔH) enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys have been determined by high-temperature isoperibolic calorimetry
at 1565 ± 5 K. The heat capacity (C
p) of liquid Ni26Zr74 has been measured by adiabatic calorimetry (C
p=53.5±2.2 J mol−1 K−1 at 1261±15 K). The integral enthalpy of mixing changes with composition from a small positive (Cu-Ni, ΔH (x
Ni=0.50, T=1473 to 1750 K)=2.9 kJ mol−1) to a moderate negative (Cu-Zr; ΔH(x
Zr=0.46, T=1485 K)=−16.2 kJ mol−1) and a high negative value (Ni-Zr; ΔH(x
Zr=0.37, T=1565 K)=−45.8 kJ mol−1). Regression analysis of new data, together with the literature data for liquid Ni-Zr alloys, results in the following relationships
in kJ mol−1 (standard states: Cu (1), Ni (1), and Zr (1)):for Ni-Zr (1281≤T≤2270 K),
for Cu-Ni-Zr (T=1565±5 K),
相似文献
6.
Hiroaki Yamamoto Masao Morishita Akio Miyata Koichiro Koyama 《Metallurgical and Materials Transactions B》2006,37(4):607-613
The standard Gibbs energies of formation of Ni3B, Ni2B, o-Ni4B3(Ni0.586B0.414), m-Ni4B3(Ni0.564B0.436), NiB, and Ni3B2O6 of the Ni-B-O system have been determined by measuring electromotive forces of galvanic cells using a Y2O3-stabilized ZrO2 solid oxide electrolyte. The results are as follows:
Temperature range: 1198 to 1298 K
Temperature range: 1182 to 1285 K
Temperature range: 1193 to 1273 K
Temperature range: 1193 to 1273 K
Temperature range: 1203 to 1253 K
Temperature range: 1182 to 1393 K where the standard pressure is 1 bar (100 kPa). 相似文献
7.
Takahiro Miki Kazuki Morita Nobuo Sano 《Metallurgical and Materials Transactions B》1998,29(5):1043-1049
The thermodynamic properties of aluminum, magnesium, and calcium in molten silicon were investigated using a chemical equilibration
technique at 1723 to 1848 K, 1698 to 1798 K, and 1723 to 1823 K, respectively. The activity coefficient of aluminum in molten
silicon was determined by equilibrating molten silicon-aluminum alloys with solid Al2O3 and Al6Si2O13, that of magnesium was determined by equilibrating molten silicon-magnesium alloys and MgO-SiO2-Al2O3 melts doubly saturated with MgSiO3 and SiO2, and that of calcium was determined by equilibrating molten silicon-calcium alloys with SiO2-saturated CaO-SiO2 melts. The activity coefficients at infinite dilution relative to the pure liquid state were determined as follows:
相似文献
8.
9.
Thermodynamics of phosphorus in molten silicon 总被引:3,自引:0,他引:3
Takahiro Miki Kazuki Morita Nobuo Sano 《Metallurgical and Materials Transactions B》1996,27(6):937-941
10.
11.
K. T. Jacob Shashank Priya Yoshio Waseda 《Metallurgical and Materials Transactions A》1998,29(6):1545-1550
The activity of rhodium in solid Pt-Rh alloys is measured in the temperature range from 900 to 1300 K using the solid-state
cell
The activity of platinum and the free energy, enthalpy, and entropy of mixing are derived. Activities exhibit moderate negative
deviation from Raoult’s law. The mixing properties can be represented by a pseudosubregular solution model in which excess
entropy has the same type of functional dependence on composition as the enthalpy of mixing,
The negative enthalpy of mixing obtained in this study is in qualitative agreement with predictions of semiempirical models
of Miedema and co-workers and Colinet et al. The results of this study do not support the solid-state miscibility gap suggested in the literature, but are consistent
with liquidus data within experimental uncertainty limits. 相似文献
12.
13.
Hiroyuki Fukuyama Hideki Tabata Kazuhiro Nagata 《Metallurgical and Materials Transactions B》2003,34(3):307-311
The standard Gibbs energy change for the following reaction has been directly determined by electromotive force (EMF) measurement
using CaF2 as the solid electrolyte in the temperature range from 1313 to 1329 K.
From the preceding results, the standard Gibbs energy of formation of cuspidine has been evaluated for the first time as
The chemical potential diagram for the CaO-SiO2-CaF2 system has been developed at 1323 K based on the thermodynamic data obtained in the present study. 相似文献
14.
Data in the literature on the Magneli oxides of titanium have been critically evaluated and equations have been developed
from these data for the standard-state Gibbs energy of formation of the following oxides: Ti4O7, Ti5O9, Ti6O11, Ti8O15, and Ti9O17. Examination of those data yielded the following:
Similar equations for Ti16O31 and Ti50O99 have been estimated from their respective data at 1304 K. The result of that analysis has lead to the following equations:
These equations, along with data in the literature, have been used to construct the Ti-O stability diagram. 相似文献
15.
Hiroaki Yamamoto Masao Morishita Takeo Yamamoto Kazuma Furukawa 《Metallurgical and Materials Transactions B》2011,42(1):114-120
The standard Gibbs energies of formation of Mo2B, ??MoB, Mo2B5, and MoB4 in the molybdenum-boron binary system were determined by measuring electromotive forces of galvanic cells using an Y2O3-stabilized ZrO2 solid oxide electrolyte. The results are as follows: $$ \begin{aligned} \Updelta_{\text{f}} {\text{G}}^\circ \left( {{\text{Mo}}_{2} {\text{B}}} \right)/{\text{J}}\,{\text{mol}}^{ - 1} & = - 193100 + 44.10T \pm 700\left( {1198{\text{ K to }}1323{\text{ K}}\left( {925^\circ {\text{C to }}1050^\circ {\text{C}}} \right)} \right) \\ \Updelta_{\text{f}} {\text{G}}^\circ (\alpha {\text{MoB}})/{\text{J}}\,{\text{mol}}^{ - 1} & = - 164000 + 26.45T \pm 700\left( {1213{\text{ K to }}1328{\text{ K}}\left( {940^\circ {\text{C to }}1055^\circ {\text{C}}} \right)} \right) \\ \Updelta_{\text{f}} {\text{G}}^\circ \left( {{\text{Mo}}_{2} {\text{B}}_{5} } \right)/{\text{J}}\,{\text{mol}}^{ - 1} & = - 622500 + 117.0T \pm 3000\left( {1205{\text{ K to }}1294{\text{ K}}\left( {932^\circ {\text{C to }}1021^\circ {\text{C}}} \right)} \right) \\ \Updelta_{\text{f}} {\text{G}}^\circ \left( {{\text{MoB}}_{4} } \right)/{\text{J}}\,{\text{mol}}^{ - 1} & = - 387300 + 93.53T \pm 3000\left( {959{\text{ K to }}1153{\text{ K}}\left( {686^\circ {\text{C to }}880^\circ {\text{C}}} \right)} \right) \\ \end{aligned} $$ where the standard pressure is 1 bar (100 kPa). 相似文献
16.
This article describes kinetic modeling of titania reduction and carburization by methane-containing gas, based on experimental
data reported previously by Zhang and Ostrovski. A sequence of titania reduction to titanium oxycarbide,
which was observed experimentally, is represented by the following two reactions:
where ss designates a solid solution and f is the molar fraction of TiC in the solid solution. A two-interface shrinking-core model and a crackling-core model are employed
for the kinetic modeling of the reduction and carburization process. The rates of Reactions [1] and [2] are both controlled
by the chemical-reaction stage. For the intrinsic chemical-reaction control, the extent of the reaction as a function of reaction
time is well described analytically. The two models give close results that are consistent with experimental data obtained
at 1473 to 1773 K and a methane partial pressure up to 8 kPa. Reaction [1] is of the first order with respect to methane and
of one-half to first order with respect to hydrogen. The apparent activation energy of reaction [1] is 124 kJ/mol for the
two-interface shrinking-core model and 126 kJ/mol for the crackling-core model. Reaction [2] is of the first order with respect
to methane and is independent of hydrogen concentration. Nevertheless, hydrogen plays an important role in the reduction/carburization
process, as it suppresses the decomposition of methane and deposition of solid carbon. The apparent activation energy of the
reaction is 161 kJ/mol for the two-interface shrinking-core model and 191 kJ/mol for the crackling-core model. 相似文献
([1]) |
([2]) |
17.
18.
G. M. Kale 《Metallurgical and Materials Transactions B》1998,29(1):31-38
Gibbs energy of formation of NiTiO3 (ilmenite) relative to its component oxides, NiO (rock salt) and TiO2 (rutile), has been measured employing the solid-state electrochemical cell,
. between 994 and 1371 K. The open-circuit electromotive force (emf) of the preceding solid-state galvanic cell was found
to be reversible and to vary linearly as a function of temperature in the range of measurement. The results obtained in this
study give for the reaction
. Combining the Gibbs energy of formation of NiTiO3 (ilm) from the component oxides with that for the formation of NiO (rs) from its elements gives for the reaction
. Differential thermal analysis (DTA) of NiTiO3 (ilm) between 373 and 1623 K indicated that NiTiO3 (ilm) undergoes a reversible order-disorder phase transformation between 1540 and 1594 K. Based on the ideal mixing of cations
on the cationic sublattice of NiTiO3 (ilm) and a critical phase transformation of 1568 K obtained from the DTA, the Gibbs energy change for the order-disorder
phase transformation in NiTiO3 (ilm) is obtained as
. 相似文献
19.
The activity of carbon in the two-phase regions W + WC and W + W2C has been obtained from the carbon content of iron rods equilibrated with mixtures of metal plus carbide powders. From this activity data the standard free energies of formation of WC and W2C have been calculated to be ΔG f 0(WC) = -10,100 + 1.19T ± 100 cal/mole (-42,300 + 4.98T ± 400 J/mole) (1150 to 1575 K) ΔG f 0(W2C) = - 7300 - 0.56T ± 100 cal/mole (- 30,500 - 2.34T ± 400 J/mole). (1575 to 1660 K) The temperature of the eutectoid reaction W2C = W + WC was fixed at 1575 ± 5K. Using available data for the solubility of C in solid W, the relative partial molar free energy of C in the dilute solid solution was calculated to be $$\Delta \bar G_C^\alpha {\text{ = 23,000 }} - {\text{ }}[{\text{0}}{\text{.68 }} - R\ln X_C^\alpha ]{\text{ }}T \pm 3000 cal/mole (96,200 - [2.85 - R\ln X_C^\alpha ]{\text{ }}T \pm 12,600 J$$ The heat solution of C in W obtained was \(\Delta \bar H_C^\alpha {\text{ = 23,000 }} \pm {\text{ 5000 cal/mole (96,200 }} \pm {\text{ 20,000 J/mole)}}\) and the excess entropy for the interstitial solid solution, assuming that the carbon atoms are in the octahedral sites, \(\Delta \bar S_C^\alpha {\text{ = (}}xs,i{\text{) }} = - {\text{1}}{\text{.5 }} \pm {\text{ 2 cal/deg - mole (}} - {\text{6}}{\text{.3 }} \pm {\text{ 8 J/deg - mole)}}\) . 相似文献
20.
William T. Donlon 《Metallurgical and Materials Transactions A》2003,34(3):523-529
Solidification of Al-Si alloys typically yields regions of a eutectic mixture of aluminum and silicon phases. In 319-type
and 356 aluminum alloys, we have determined that a small percentage (10 to 25 pct) of the silicon phase contains small (10
to 15 nm) equiaxed precipitates of aluminum as identified by electron diffraction with an orientation relation to the silicon
matrix:
. These precipitates are typically distributed in bands in the silicon and their morphology is insensitive to solidification
time and subsequent heat treatments. Energy-dispersive X-ray (EDX) analysis showed that, depending on the alloy, these precipitates
contained aluminum, copper, and traces of oxygen. 相似文献