The synthesis, structure, and characterization of α″‐Fe16N2 (invited)
The synthesis, structure, and characterization of α″‐Fe16N2 (invited)
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DOI：
10.1063/1.358482
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发表时间：
1994-11
影响因子：
3.2
通讯作者：
K. Jack
中科院分区：
文献类型：
--
作者：
K. Jack
关于α ′-Fe 16 N2薄膜的磁性的争议使得期望检查块体材料。在1951年α'的原始制备和晶体结构测定中，将α-铁粉在700-750 °C氮化制备的N-奥氏体（γ）淬火得到N-马氏体（γ'），然后在120 °C长时间回火得到α+α'。最终产物是α+α'或α+ γ'+ γ的混合物，其中γ '小于50%。最近在三个不同的实验室中重复了这种制备方法，得到了具有不同量的α '的混合物，也从未超过50%，并且具有α'的磁矩-从对混合物进行的测量中评估-显示出相当大的变化。通过XRD对α'回火的研究和通过高分辨率TEM对过饱和N铁素体（α）中α'沉淀的研究都表明，只有在α'和α的局部区域通过簇集过程达到Fe 8 N成分后，N原子才缓慢有序化以产生α'。因此，可以获得具有四方性c/a等于...
Controversy about the magnetic properties of α‘‐Fe16N2 thin films makes it desirable to examine bulk material. In the original preparation and crystal structure determination of α‘ in 1951, N‐austenite (γ) prepared by nitriding α‐iron powder at 700–750 °C was quenched to give N‐martensite (α’) which then gave α+α‘ on long tempering at 120 °C. The final product was a mixture of either α+α‘ or α+α‘+γ with less than 50%α‘. Recent repetitions of this preparative method in three different laboratories have given mixtures with varying amounts of α‘, again never greater than 50%, and with magnetic moments of α‘—assessed from measurements made on the mixtures—that show considerable variation. Studies of α’ tempering by XRD, and of α‘ precipitation from supersaturated N ferrite (α) by high‐resolution TEM, both show that slow ordering of N atoms to produce α‘ occurs only after localized regions of α’ and α reach the Fe8N composition by a clustering process. Thus α’‐Fe8N can be obtained with a tetragonality c/a equa...