SmCox-0.4Ti0.4合金薄带的相结构和磁性能

SmCo_x-0.4Ti_0.4(x=5.0, 5.5, 6.5, 7.0)合金经42m/s速度甩带快速凝固制成薄带,在真空热处理炉中,进行750℃两小时热处理.对制得的甩带状态和热处理状态合金薄带分别测试其相结构和磁性能.结果表明:SmCo_x-0.4Ti_0.4合金甩带状态样品相结构随Co含量的不同而变化,其中x=5.0,5.5和6.5的合金样品由2∶ 17和1∶ 5两相结构组成;x=7.0成分样品由1∶ 7单相结构组成.甩带状态样品的比饱和磁化强度和比剩余磁化强度基本上线性增加,内禀矫顽力在合金成分为x=5.0时出现最大值,为1.01T.薄带样品热处理前后均具有纳米晶结构,表现出剩磁增强效应.样品矫顽力机制主要为形核型,反磁化形核场主要来源于SmCo硬磁相大的磁晶各向异性及其纳米晶结构.热处理后,除x=7.0样品外,其余样品矫顽力均有所下降.

Phase structure and magnetic properties of SmCo x-0.4 Ti0.4 ribbons

SmCo_x-0.4Ti_0.4(x=5.0,5.5,6.5 and 7.0) ribbons were prepared by melt-spinning at a wheel speed of 42m/s, followed by annealing at 750℃ for 2 h.The phase structure and magnetic properties were measured for two types of ribbons, the as-spun and the as-spun/annealed. It was found that the phase structure of the as-spun ribbons changed with the Co content increasing. The as-spun samples with x=5.0, 5.5 and 6.5 showed a 1∶ 5 plus 2∶ 17 phase structure. The x=7.0 ribbons presented a single 1∶ 7 phase structure. The specific saturation magnetization and the specific remanence increased almost linearly with the increasing of Co content. The maximum intrinsic coercivity of 1.01 T was obtained in the as-spun ribbons with x=5.0. Both of the two types showed a fine nanograin microstructure, and leaded to the remanence enhancement. The coercivity mechanism of the ribbons was mainly of the nucleation type, and the reversal magnetization nucleation field arised from the high uniaxial magnetocrystalline anisotropy of the hard phases and the nanograin microstructures. The intrinsic coercivities decreased after annealing, except the sample with x=7.0.