| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1988: ¥100,000 (Direct Cost: ¥100,000)
Fiscal Year 1987: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
Diffusion of Sm in Co was investigated as a basic study of the reductiondiffusion process for the produc-tion of magnet materials.
Firstly, a Co block was put in contack with a liquis Sm-Ca alloy. However, before the occurrence of the diffusion of Sm, the contact surface of the Co block unevenly dissolved in the liquid alloy and the diffusion layers thus obtained were very irregular in thickness. Secondly, therefore, a Co block was put in contact with the vapor from the liquid Sm-Ca alloy, then the dissolution of the Co block could be suppressed and fairly even diffusion layers were obtained. This second procedure was exclusively adopted thereafter.
The SmCo_5 phase grew most rapidly and the Sm_2Co_<17> phase grew much slower in fron of the SmCo_5 phase. Diffusion coefficients of Sm in the SmCo_5 and the Sm_2Co_<17> phases were determined at 1050, 1100, and 1150 ゜C.
In association with the procedure in this study, the reduction-diffusion process was conducted by separately heating a Sm_2O_3-Ca mixture and Co powder, then a Co-Sm alloy was obtained which contained less calcarious substance than those prepared in the usual reduction-diffusion process. This procedure should be called the 'reduction-vaporization-diffusion process' and seems to be useful when the diffusing substance is comparatively volatile like Sm. It was also found that, when a Co block in which the SmCo_5 layer was the thickest was heated at 1100-1200 ゜C without supplying Sm vapor, Sm in the SmCo_5 phase diffused in the remaining Co and the Sm_2Co_<17> phase became the largest in a few hours. These two findings may be clues to the production of the Sm_2Co_<17> type magnet materials by the reduction-diffusion process, which has not been sucessful so far, and will be investigated in the future.
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