Crystallization and structure of high boron content iron-boron ultrafine amorphous alloy particles
Crystallization and structure of high boron content iron-boron ultrafine amorphous alloy particles
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高硼铁硼超细非晶合金颗粒的结晶及结构
DOI：
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发表时间：
1996
影响因子：
4.5
通讯作者：
Y. Chen
中科院分区：
文献类型：
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作者：
Z. Hu;Y. Fan;Y. Wu;Q. Yan;Y. Chen
通过穆斯堡尔光谱、Brunauer-Emmett-Teller 表面积测量和透射电子显微镜研究了化学制备的 Fe64B36 超细非晶态合金颗粒的非晶态到晶态转变。在低于 350°C 时观察到结构弛豫，这导致超精细场分布的半峰全宽从 13.0 T 缩小到 10.6 T，而平均超精细场保持不变，为约 20.3 T。结晶在约 300°C 时在表面开始，并在约 400°C 时进入本体。 400 至 450°C 之间的部分结晶导致剩余 Fe-B 非晶基体的平均超精细场增加至 21.6 T。α-Fe 和 Fe2B 是唯一与块体结晶相关的含铁相，后者为主要成分，并伴有约 19% 硼原子的偏析。在500℃以上，颗粒的烧结变得非常明显，扩散的铁和硼原子之间发生固态反应形成Fe2B，使得Fe2B与α-Fe组分的光谱面积比相应增加。提出了高硼含量样品的局部扭曲非化学计量 Fe2B 准晶结构。
Amorphous to crystalline transformation of chemically prepared Fe64B36 ultrafine amorphous alloy particles has been investigated by Mössbauer spectroscopy, Brunauer-Emmett-Teller surface area measurements and transmission electron microscopy. Structural relaxation was observed below 350°C, which resulted in narrowing the full width at half maximum for the hyperfine field distribution from 13.0 to 10.6 T, while the average hyperfine field kept unchanged, to be about 20.3 T. Crystallization started on the surface at about 300°C and proceeded into the bulk at about 400°C. Partial crystallization between 400 and 450°C resulted in increasing the average hyperfine field for the remaining Fe-B amorphous matrix to 21.6 T. α-Fe and Fe2B were the only iron containing phases related to bulk crystallization, with the latter as a predominant component, accompanied by the segregation of about 19% boron atoms. Above 500°C, sintering of the particles became very remarkable and a solid state reaction between diffusing iron and boron atoms to form Fe2B took place making the spectral area ratio for Fe2B to α-Fe components increase accordingly. A locally distorted non-stoichiometric Fe2B quausicrystalline structure for the high boron content sample was proposed.