Carbon solubility in Fe-Mn melts （XFe =0. 102 3-0. 789 9, XMn =0. 055 1-0. 638 0） was measured experimentally at various temperatures. Using Gibbs-Duhem equation, in combination with the experimental results in this...Carbon solubility in Fe-Mn melts （XFe =0. 102 3-0. 789 9, XMn =0. 055 1-0. 638 0） was measured experimentally at various temperatures. Using Gibbs-Duhem equation, in combination with the experimental results in this work, quoting experimental data reported in references, and by strict thermodynamic derivation and calculation, the relation equations between the activity interaction parameters in Fe-C system and temperature were obtained. The calculation equation of lnyFe. in Fe-C system was also obtained. The calculated results show that these relation equations can be used to calculate the activity coefficients of carbon and iron in Fe-C system and can satisfy the necessary condition to satisfy Gibbs-Duhem equation and the necessary condition to satisfy the stability condition of system at high carbon content. The calculation formula for lnTc in Fe-Mn-C system was also obtained.展开更多
In this study,Fe-C core-shell nanoparticles with identical metal core sizes and C shell thicknesses but varying degrees of graphitization of C shells were fabricated using metal-organic chemical vapor depo-sition and ...In this study,Fe-C core-shell nanoparticles with identical metal core sizes and C shell thicknesses but varying degrees of graphitization of C shells were fabricated using metal-organic chemical vapor depo-sition and subsequent annealing.Due to the identical metal core,these nanoparticles exhibite a similar permeability,but significantly varying permittivity depending on how much C shells have been graphi-tized.It was discovered that proper graphitization of Fe-C nanoparticles annealed at 1350 ℃ can pro-duce excellent microwave absorption(MA),decent dielectric loss tangent in high frequency region,and moderately strong dielectric loss and attenuation properties.Furthermore,the threshold value of 1/ω is discovered to be a crucial parameter in the theoretical analysis of nonlinear behavior of polarization loss,and thus MA performance of the nanoparticles.This research offers a useful method for creating metal-C nanoparticles with various levels of C shell graphitization.It also provides a clear answer to the crucial question of how the level of C shell graphitization affects the MA performance of metal-C nanoparticles.These results may serve as a reference for the development and mechanism analysis of highly effective metal-C based absorbers.展开更多
基金Item Sponsored by National Natural Science Foundation of China (50374002)
文摘Carbon solubility in Fe-Mn melts （XFe =0. 102 3-0. 789 9, XMn =0. 055 1-0. 638 0） was measured experimentally at various temperatures. Using Gibbs-Duhem equation, in combination with the experimental results in this work, quoting experimental data reported in references, and by strict thermodynamic derivation and calculation, the relation equations between the activity interaction parameters in Fe-C system and temperature were obtained. The calculation equation of lnyFe. in Fe-C system was also obtained. The calculated results show that these relation equations can be used to calculate the activity coefficients of carbon and iron in Fe-C system and can satisfy the necessary condition to satisfy Gibbs-Duhem equation and the necessary condition to satisfy the stability condition of system at high carbon content. The calculation formula for lnTc in Fe-Mn-C system was also obtained.
基金Hunan Provincial Natural Science Foundation of China(Nos.2022JJ40121,2021JJ40153 and 2021JJ50108)Scientific Research Fund of Hunan Provincial Education Department(Nos.21B0657,22A0518).
文摘In this study,Fe-C core-shell nanoparticles with identical metal core sizes and C shell thicknesses but varying degrees of graphitization of C shells were fabricated using metal-organic chemical vapor depo-sition and subsequent annealing.Due to the identical metal core,these nanoparticles exhibite a similar permeability,but significantly varying permittivity depending on how much C shells have been graphi-tized.It was discovered that proper graphitization of Fe-C nanoparticles annealed at 1350 ℃ can pro-duce excellent microwave absorption(MA),decent dielectric loss tangent in high frequency region,and moderately strong dielectric loss and attenuation properties.Furthermore,the threshold value of 1/ω is discovered to be a crucial parameter in the theoretical analysis of nonlinear behavior of polarization loss,and thus MA performance of the nanoparticles.This research offers a useful method for creating metal-C nanoparticles with various levels of C shell graphitization.It also provides a clear answer to the crucial question of how the level of C shell graphitization affects the MA performance of metal-C nanoparticles.These results may serve as a reference for the development and mechanism analysis of highly effective metal-C based absorbers.
