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合金成份固然是决定磁性好坏的内因,但必须通过相应的最佳热处理方能充分发挥出合金的优良磁性能。铝镍钴系永磁合金是脱溶硬化型合金。高温状态下过饱和的单一固溶体α相(体心立方),在适当的条件下可以按α→α_1+α_2分解。其中α_1是体心立方的富 Fe、Co 的强磁性单畴微粒相;其中α_2是体心立方的弱磁性(或无磁性)的富 Ni、Al 和 Ti(或无 Ti)的母相。α_1相是具有各向异性的相,必须弥散地分布在弱磁性的α_2相基体里。在高温单相区和α→α_1+α_2分解温度区之间存在一个α→γ反应的温度区,γ相是面心立方的有害相,在室温下它转变为同素异形体的α_r相,α_r 相仍为有害相。整个热处理过程,就是抑制有害相(γ相)的析出,保证在单一的α相的前提下实现α→α_1+α_2分解,保证磁硬化的基本条件。
Of course, the composition of the alloy is to determine the magnetic properties of good or bad, but must be through the appropriate heat treatment can give full play to the excellent magnetic properties of the alloy. Alnico permanent magnet alloy is a solution hardening alloy. The single solid solution alpha phase (body centered cubic) supersaturated at high temperature can be decomposed by α → α_1 + α_2 under appropriate conditions. Wherein α_1 is a body-centered cubic Fe-Co rich ferromagnetic monoparticulate particulate phase; wherein α_2 is a body-centered cubic weakly magnetic (or nonmagnetic) Ni, Al and Ti (or Ti-free) parent phase. The α_1 phase is an anisotropic phase and must be dispersedly distributed in the weakly magnetic α_2 phase matrix. There is an α → γ reaction between the high temperature single-phase region and the α → α_1 + α_2 decomposition temperature region. The γ phase is a face-centered cubic harmful phase. At room temperature, it changes to allotrope α_r. α_r phase is still harmful phase. The whole heat treatment process is to suppress the precipitation of harmful phase (γ phase), to ensure α α α 1 α α 2 decomposition under the premise of a single phase to ensure the basic conditions of magnetic hardening.