Microstructure dependent on silicon and formation of 1：13 phase in LaFe13-ySiyC0.2 compounds was investigated. C and Si elements played different roles in assisting the formation of 1：13 phase. Si could inhibit the ...Microstructure dependent on silicon and formation of 1：13 phase in LaFe13-ySiyC0.2 compounds was investigated. C and Si elements played different roles in assisting the formation of 1：13 phase. Si could inhibit the growth of α-Fe. The volume fraction of La-rich phase increased with the increase of Si content in the LaFe13-ySiyC0.2 ingots. When Si content was lower in LaFe13-ySiyC0.2 （S≤1.0）, α-Fe was excess and grew very large in the initial annealing process. As a result, a large amount of α-Fe remained even after a long time annealing process. Carbon doping could accelerate the formation of 1：13 phase in the LaFe13-ySiyC0.2 compounds. The amount of the 1：13 phase reached -90 vol.% in LaFex3_ySiyC02 （y〉1.2） after annealing at 1353 K for only 3 d. After optimized annealing, large magnetic entropy changes were obtained in LaFe13-SiyC0.2 compounds （18.6 and 15 J/（kg.K） in 0-2 T field change fory=1.2, 1.4, respectively）.展开更多
基金Project supported by National Natural Science Foundation of China (50731007,50971022) the National High Technology Research and Development Program of China (2011AA03A404)the Fundamental Research Funds for the Central Universities
文摘Microstructure dependent on silicon and formation of 1：13 phase in LaFe13-ySiyC0.2 compounds was investigated. C and Si elements played different roles in assisting the formation of 1：13 phase. Si could inhibit the growth of α-Fe. The volume fraction of La-rich phase increased with the increase of Si content in the LaFe13-ySiyC0.2 ingots. When Si content was lower in LaFe13-ySiyC0.2 （S≤1.0）, α-Fe was excess and grew very large in the initial annealing process. As a result, a large amount of α-Fe remained even after a long time annealing process. Carbon doping could accelerate the formation of 1：13 phase in the LaFe13-ySiyC0.2 compounds. The amount of the 1：13 phase reached -90 vol.% in LaFex3_ySiyC02 （y〉1.2） after annealing at 1353 K for only 3 d. After optimized annealing, large magnetic entropy changes were obtained in LaFe13-SiyC0.2 compounds （18.6 and 15 J/（kg.K） in 0-2 T field change fory=1.2, 1.4, respectively）.
