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结合高能球磨和放电等离子烧结技术,通过非晶合金粉末在烧结致密化的同时发生完全纳米晶化的机制,制备出了致密的SmCo_2纳米晶合金块体材料,其平均晶粒尺寸约22 nm.对SmCo_2纳米晶合金化合物的显微组织、晶体结构和相组成等的表征和分析表明,SmCo_2纳米晶合金在室温下不能以单相的形式存在,发生分解形成SmCo_3,Sm_9Co_4和SmCo_2多相共存的合金体系;而粗晶合金可以SmCo_2单相在室温下稳定存在.结合纳米晶热力学计算阐释了粗晶合金和纳米晶合金的相稳定性及其转变规律.对磁性能的测定表明,与同种成分粗晶合金只有微弱的磁性能相比,SmCo_2纳米晶合金表现出明显的永磁特性,且具有良好的综合磁性能.
In combination with high-energy ball milling and spark plasma sintering, a compact SmCo_2 nanocrystalline alloy bulk material with a mean grain size of about 22 nm was prepared by the mechanism of complete nanocrystallization of amorphous alloy powder during sintering densification. The characterization and analysis of the microstructure, crystal structure and phase composition of SmCo_2 nanocrystalline alloy show that the SmCo_2 nanocrystalline alloy can not exist in single phase at room temperature and decompose to form multiphase SmCo 3, Sm 9 Co 4 and SmCo 2 phases Alloy system, while the coarse-grained alloy can exist stably at single-phase of SmCo_2 at room temperature.The phase stability and transformation of coarse-grained alloy and nanocrystalline alloy are explained by the thermodynamic calculation of nanocrystalline.The determination of magnetic properties shows that, SmCo_2 nanocrystalline alloy shows obvious permanent magnet properties and has good comprehensive magnetic properties compared with the weak magnetic properties of coarse-grained alloy.