The amount of literature on both melting and thermal conductivity of iron at Earth’s core conditions is overwhelming and the discrepancies are very large.There is a broad range of experimental techniques each of whic...The amount of literature on both melting and thermal conductivity of iron at Earth’s core conditions is overwhelming and the discrepancies are very large.There is a broad range of experimental techniques each of which is flawed to a certain degree,which may explain the discrepancy.In this report,we present new data using a different method for determining the phase behavior and resistivity of iron in the laser-heated diamond cell by measuring the electrical resistance of both solid and liquid iron wires.The experiment avoids some of the major flaws of previous experiments,the most important of which is the detection of the onset of melting.These measurements confirm a shallow melting curve found earlier and the resistivity data imply a trend towards low thermal conductivity in the liquid outer core.展开更多
Long-term thermal stability of a series of Zr-based metallic glasses with different oxygen contents below their glass transition temperatures was compared based on their deductive continuous-heating-transformation dia...Long-term thermal stability of a series of Zr-based metallic glasses with different oxygen contents below their glass transition temperatures was compared based on their deductive continuous-heating-transformation diagrams created by using the corollary of Kissinger analysis method. It is found that the influence of oxygen on the long-term thermal stability of Zr-based metallic glasses exhibits at lower temperature is different from that on their short-term thermal stability presented at higher temperature. For each kind of the Zr-based metallic glasses, there is a critical heating rate, φ , which corresponds to a critical c temperature, Tc. As heating rate is smaller than φ c and onset devitrification temperature is below Tc, the glass with higher oxygen content will have longer incubation period for onset devitrification. The values of φ c and Tc are related with the glasses’ reduced glass transition temperature Trg. The improving effect of oxygen impurity on the long-term thermal stability of Zr-based metallic glasses was discovered.展开更多
Phase equilibrium in the ternary CuO-PbO-Ag system has been investigated using differential thermal analysis(DTA),thermogravimetry(TG),scanning electron microscopy(SEM) and X-ray diffraction(XRD) techniques.In the ter...Phase equilibrium in the ternary CuO-PbO-Ag system has been investigated using differential thermal analysis(DTA),thermogravimetry(TG),scanning electron microscopy(SEM) and X-ray diffraction(XRD) techniques.In the ternary CuO-PbO-Ag system,there is a eutectic reaction CuO+PbO+Ag=L at 750℃ and a composition of 12.04 mol.% Ag,16.35 mol.% CuO and 71.61 mol.% PbO.Two miscibility gaps near the two binary tie lines PbO-Ag and CuO-Ag were detected. No binary or ternary compound was detected in the ternary system.SEM and energy dispersive spectroscopy(EDS) confirm the presence of two liquid phases and the eutectic point.展开更多
The phase equilibrium data on organic analog of the nonmetal-nonmetal system, involving 2-cyanoacetamide (CA)―4-chloronitrobenzene (CNB), show the formation of a monotectic (0.10 mole fraction of CNB) and a eutectic ...The phase equilibrium data on organic analog of the nonmetal-nonmetal system, involving 2-cyanoacetamide (CA)―4-chloronitrobenzene (CNB), show the formation of a monotectic (0.10 mole fraction of CNB) and a eutectic (0.98 mole fraction of CNB) with a large miscibility gap starting from 0.10 mole fraction of CNB of monotectic (M) and ending at 0.92 mole fraction of CNB of monotectic horizontal (Mh);the upper consolute temperature Tc being 63?C above the monotectic horizontal at 118?C and eutectic temperature is at 85?C. The values of enthalpy of fusion of the pure components, the eutectic and the monotectic were determined by the differential scanning calorimetry (Mettler DSC-4000 system). Using these data, the size of the critical radius, interfacial energy, excess thermodynamic functions, entropy of fusion, and enthalpy of mixing were calcu-lated. The solid-liquid interfacial energy data confirm the applicability of the Cahn wetting condition. While growth data obey the Hillig-Turnbull equation, the microstructural investigations give typical characteristic features of the eutectic and the monotectic of the system.展开更多
The phase diagram of the CsBr-CaBr2 system was re-determined by using differential thermal analysis and high ternperature and room ternperature X-ray diffraction analysis. It is concluded that there are three intermed...The phase diagram of the CsBr-CaBr2 system was re-determined by using differential thermal analysis and high ternperature and room ternperature X-ray diffraction analysis. It is concluded that there are three intermediate compounds in this system： a.congruently melting compound, CsCaBr3, with a melting point of 823℃ and two incongruently melting compounds, Cs2CaBr4 and Cs3Ca2Br7, whose peritectic points being 597℃ and 635℃, respectively. X-ray diffraction analysis indicated that compound CsCaBr3 is of slightly distorted perovskite structure.展开更多
基金supported by the National Science Foundation (No. 1248553)
文摘The amount of literature on both melting and thermal conductivity of iron at Earth’s core conditions is overwhelming and the discrepancies are very large.There is a broad range of experimental techniques each of which is flawed to a certain degree,which may explain the discrepancy.In this report,we present new data using a different method for determining the phase behavior and resistivity of iron in the laser-heated diamond cell by measuring the electrical resistance of both solid and liquid iron wires.The experiment avoids some of the major flaws of previous experiments,the most important of which is the detection of the onset of melting.These measurements confirm a shallow melting curve found earlier and the resistivity data imply a trend towards low thermal conductivity in the liquid outer core.
基金Project(50671076) supported by the National Natural Science Foundation of China
文摘Long-term thermal stability of a series of Zr-based metallic glasses with different oxygen contents below their glass transition temperatures was compared based on their deductive continuous-heating-transformation diagrams created by using the corollary of Kissinger analysis method. It is found that the influence of oxygen on the long-term thermal stability of Zr-based metallic glasses exhibits at lower temperature is different from that on their short-term thermal stability presented at higher temperature. For each kind of the Zr-based metallic glasses, there is a critical heating rate, φ , which corresponds to a critical c temperature, Tc. As heating rate is smaller than φ c and onset devitrification temperature is below Tc, the glass with higher oxygen content will have longer incubation period for onset devitrification. The values of φ c and Tc are related with the glasses’ reduced glass transition temperature Trg. The improving effect of oxygen impurity on the long-term thermal stability of Zr-based metallic glasses was discovered.
文摘Phase equilibrium in the ternary CuO-PbO-Ag system has been investigated using differential thermal analysis(DTA),thermogravimetry(TG),scanning electron microscopy(SEM) and X-ray diffraction(XRD) techniques.In the ternary CuO-PbO-Ag system,there is a eutectic reaction CuO+PbO+Ag=L at 750℃ and a composition of 12.04 mol.% Ag,16.35 mol.% CuO and 71.61 mol.% PbO.Two miscibility gaps near the two binary tie lines PbO-Ag and CuO-Ag were detected. No binary or ternary compound was detected in the ternary system.SEM and energy dispersive spectroscopy(EDS) confirm the presence of two liquid phases and the eutectic point.
文摘The phase equilibrium data on organic analog of the nonmetal-nonmetal system, involving 2-cyanoacetamide (CA)―4-chloronitrobenzene (CNB), show the formation of a monotectic (0.10 mole fraction of CNB) and a eutectic (0.98 mole fraction of CNB) with a large miscibility gap starting from 0.10 mole fraction of CNB of monotectic (M) and ending at 0.92 mole fraction of CNB of monotectic horizontal (Mh);the upper consolute temperature Tc being 63?C above the monotectic horizontal at 118?C and eutectic temperature is at 85?C. The values of enthalpy of fusion of the pure components, the eutectic and the monotectic were determined by the differential scanning calorimetry (Mettler DSC-4000 system). Using these data, the size of the critical radius, interfacial energy, excess thermodynamic functions, entropy of fusion, and enthalpy of mixing were calcu-lated. The solid-liquid interfacial energy data confirm the applicability of the Cahn wetting condition. While growth data obey the Hillig-Turnbull equation, the microstructural investigations give typical characteristic features of the eutectic and the monotectic of the system.
文摘The phase diagram of the CsBr-CaBr2 system was re-determined by using differential thermal analysis and high ternperature and room ternperature X-ray diffraction analysis. It is concluded that there are three intermediate compounds in this system： a.congruently melting compound, CsCaBr3, with a melting point of 823℃ and two incongruently melting compounds, Cs2CaBr4 and Cs3Ca2Br7, whose peritectic points being 597℃ and 635℃, respectively. X-ray diffraction analysis indicated that compound CsCaBr3 is of slightly distorted perovskite structure.
