In recent years,lakes,including salted,attract the attention of researchers,also when reconstructing last climate changes using the bottom sediments(Solotchina et al.,2008,et al.).In this case the different geochemical
The carbon dissolution in solvent plays a key role in the process of solution growth route for SiC single crystal,which could determine the growth rate and quality of the products.However,the carbon dissolving ability...The carbon dissolution in solvent plays a key role in the process of solution growth route for SiC single crystal,which could determine the growth rate and quality of the products.However,the carbon dissolving ability of binary alloy solvent still needs to be improved.Here,we demonstrate the improved carbon dissolution and enlarged carbon supersaturation in Cr-Ce-Si ternary solvent,showing great potential for SiC solution growth.The phase relations of Cr-Ce-Si-C system were determined by using CALPHAD method based on thermodynamic parameters of CeCr_(2)Si_(2)C.It is indicated that the Cr-Ce-Si ternary solvent shows much larger carbon solubility in temperature range from 1700 to 2000℃compared to Cr-Si binary one,Furthermore,the carbon supersaturation in solvent is also significantly increased in low temperature range after the addition of Ce,leading to a rapid growth rate.Our work not only demonstrates the feasibility of adding Ce in the alloy solvent for rapid growth of SiC crystal,but also provides an example for investigating the C solubility in ternary solvent.展开更多
The reaction abilities of structural units in Fe-C binary melts over a temperature range above the liquidus lines have been evaluated by a thermodynamic model for calculating the mass action concentrations Ni of struc...The reaction abilities of structural units in Fe-C binary melts over a temperature range above the liquidus lines have been evaluated by a thermodynamic model for calculating the mass action concentrations Ni of structural units in Fe-C binary melts based on the atom-molecule coexistence theory （AMCT）, i.e., the AMCT-N/model, through comparing with the predicted activities aR.i of both C and Fe by 14 collected models from the literature at four temperatures of 1833, 1873, 1923, and 1973 K. Furthermore, the Raoultian activity coefficient γC0 of in infinitely dilute Fe-C binary melts and the standard molar Gibbs free energy change △solG%m,Cdis（1）→[C]W[C]=1.0 of dissolved liquid C for forming w[C] as 1.0 in Fe-C binary melts referred to 1 mass% of C as reference state have also been determined to be valid. The determined activity coefficient In γC of C and activity coefficient In TEe of Fe including temperature effect for Fe-C binary melts can be described by a quadratic polynomial function and a cubic polynomial function, respectively.展开更多
基金supported by integrated project no. 56 of the Siberian Branch, Russian Academy of Sciences "Forecasted modeling and multidisciplinary research of several years dynamic of meromictic lakes ecosystems state in Siberia"
文摘In recent years,lakes,including salted,attract the attention of researchers,also when reconstructing last climate changes using the bottom sediments(Solotchina et al.,2008,et al.).In this case the different geochemical
基金supported by the Beijing Municipal Science and Technology Commission Project(Z211100004821004)the National Natural Science Foundation of China(51872028)。
文摘The carbon dissolution in solvent plays a key role in the process of solution growth route for SiC single crystal,which could determine the growth rate and quality of the products.However,the carbon dissolving ability of binary alloy solvent still needs to be improved.Here,we demonstrate the improved carbon dissolution and enlarged carbon supersaturation in Cr-Ce-Si ternary solvent,showing great potential for SiC solution growth.The phase relations of Cr-Ce-Si-C system were determined by using CALPHAD method based on thermodynamic parameters of CeCr_(2)Si_(2)C.It is indicated that the Cr-Ce-Si ternary solvent shows much larger carbon solubility in temperature range from 1700 to 2000℃compared to Cr-Si binary one,Furthermore,the carbon supersaturation in solvent is also significantly increased in low temperature range after the addition of Ce,leading to a rapid growth rate.Our work not only demonstrates the feasibility of adding Ce in the alloy solvent for rapid growth of SiC crystal,but also provides an example for investigating the C solubility in ternary solvent.
基金This work is supported by the Beijing Natural Science Foundation （Grant No. 2182069） and the National Natural Science Foundation of China （Grant No. 51174186）.
文摘The reaction abilities of structural units in Fe-C binary melts over a temperature range above the liquidus lines have been evaluated by a thermodynamic model for calculating the mass action concentrations Ni of structural units in Fe-C binary melts based on the atom-molecule coexistence theory （AMCT）, i.e., the AMCT-N/model, through comparing with the predicted activities aR.i of both C and Fe by 14 collected models from the literature at four temperatures of 1833, 1873, 1923, and 1973 K. Furthermore, the Raoultian activity coefficient γC0 of in infinitely dilute Fe-C binary melts and the standard molar Gibbs free energy change △solG%m,Cdis（1）→[C]W[C]=1.0 of dissolved liquid C for forming w[C] as 1.0 in Fe-C binary melts referred to 1 mass% of C as reference state have also been determined to be valid. The determined activity coefficient In γC of C and activity coefficient In TEe of Fe including temperature effect for Fe-C binary melts can be described by a quadratic polynomial function and a cubic polynomial function, respectively.
