Thermodynamics and kinetics for the preparation of Sm2Fe17 alloys by reduction-diffusion （R-D） method in CaSm2O3-Fe System were investigated. With increasing reaction temperature, it is found that the reaction rate ...Thermodynamics and kinetics for the preparation of Sm2Fe17 alloys by reduction-diffusion （R-D） method in CaSm2O3-Fe System were investigated. With increasing reaction temperature, it is found that the reaction rate of R-D and the amount of Sm in the Sm2Fe17 alloy increase, and the increased amount at lower temperature is higher than that at higher temperature. Moreover, results from contracting core modal show that the peritectic reaction between Sm and Fe is a ratedetermined step in the whole R-D process. The apparent activation energy and the pre-exponential factor for this reaction are 73.74 kJ· mol^ -1 and 7.79 × 10^- 3 respectively.展开更多
The pure intermetallic compounds (Tb1-x;Dyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2 and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and...The pure intermetallic compounds (Tb1-x;Dyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2 and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and TbFe2 preparation by reduction-diffusion in Ca-Dy2O3-Fe and Ca-Tb4O7-Fe systems were analyzed and the products of DyFe2 and TbFe2 were confirmed by XRD. The contracting core model was applied to describe the reduction-diffusion process in which the diffusion is a rate-controlled step. The apparent activation energies of DyFe2 and TbFe2 processes are 45 and 39 kJ/mol respectively.展开更多
The pure TbFe 2 is a sort of intermetallic compound to produce (TbDy)Fe 2. It has important practical meanings to develop a new method for producing pure TbFe 2 directly from Tb 4O 7 with low cost and non pollu...The pure TbFe 2 is a sort of intermetallic compound to produce (TbDy)Fe 2. It has important practical meanings to develop a new method for producing pure TbFe 2 directly from Tb 4O 7 with low cost and non pollution. Based on our previous thermodynamic study on the production of TbFe 2 by reduction diffusion in Ca Tb 4O 7 Fe system, kinetics has been further studied in this work. It is confirmed that the product is TbFe 2 by means of XRD. The contracting core model is applied. The reactions are found to be diffusion controlled. The apparent activation energy of TbFe 2 is 39 kJ·mol -1 .展开更多
文摘Thermodynamics and kinetics for the preparation of Sm2Fe17 alloys by reduction-diffusion （R-D） method in CaSm2O3-Fe System were investigated. With increasing reaction temperature, it is found that the reaction rate of R-D and the amount of Sm in the Sm2Fe17 alloy increase, and the increased amount at lower temperature is higher than that at higher temperature. Moreover, results from contracting core modal show that the peritectic reaction between Sm and Fe is a ratedetermined step in the whole R-D process. The apparent activation energy and the pre-exponential factor for this reaction are 73.74 kJ· mol^ -1 and 7.79 × 10^- 3 respectively.
文摘The pure intermetallic compounds (Tb1-x;Dyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2 and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and TbFe2 preparation by reduction-diffusion in Ca-Dy2O3-Fe and Ca-Tb4O7-Fe systems were analyzed and the products of DyFe2 and TbFe2 were confirmed by XRD. The contracting core model was applied to describe the reduction-diffusion process in which the diffusion is a rate-controlled step. The apparent activation energies of DyFe2 and TbFe2 processes are 45 and 39 kJ/mol respectively.
文摘The pure TbFe 2 is a sort of intermetallic compound to produce (TbDy)Fe 2. It has important practical meanings to develop a new method for producing pure TbFe 2 directly from Tb 4O 7 with low cost and non pollution. Based on our previous thermodynamic study on the production of TbFe 2 by reduction diffusion in Ca Tb 4O 7 Fe system, kinetics has been further studied in this work. It is confirmed that the product is TbFe 2 by means of XRD. The contracting core model is applied. The reactions are found to be diffusion controlled. The apparent activation energy of TbFe 2 is 39 kJ·mol -1 .
