Phase relations of iron and iron-nickel alloys up to 300 GPa: Implications for composition and structure of the Earth's inner core
Phase relations of iron and iron-nickel alloys up to 300 GPa: Implications for composition and structure of the Earth's inner core
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DOI：
10.1016/j.epsl.2008.07.001
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发表时间：
2008-09-15
影响因子：
5.3
通讯作者：
Ohishi, Yasuo
中科院分区：
文献类型：
--
作者：
Kuwayama, Yasuhiro;Hirose, Kei;Ohishi, Yasuo
我们利用激光加热的金刚石-砧细胞研究了镍含量为18% ~ 50%，高达300 GPa的铁-镍合金和铁-镍合金的相关系。同步x射线衍射测量表明，hcp-iron在301 GPa和2000 K、319 GPa和300 K范围内具有广泛的稳定性，而不会发生dhcp、正交或bcc相的相变。另一方面，镍的掺入对扩大催化裂化相的稳定场有显著的作用。铁-镍合金的温度-成分相图表明，hcp-fcc-液相三相点位于10 ~ 20wt .% Ni的内芯边界压力处。催化裂化相的结晶取决于地核中镍和硅的含量，两者都是催化裂化稳定剂。(C) 2008 Elsevier B.V.版权所有
We have investigated the phase relations of iron and iron-nickel alloys with 18 to 50 wt.% Ni up to over 300 GPa using a laser-heated diamond-anvil cell. The synchrotron X-ray diffraction measurements show the wide stability of hcp-iron up to 301 GPa and 2000 K and 319 GPa and 300 K without phase transition to dhcp, orthorhombic, or bcc phases. On the other hand, the incorporation of nickel has a remarkable effect on expanding the stability field of fcc phase. The geometry of the temperature-composition phase diagram of iron-nickel alloys suggests that the hcp-fcc-liquid triple point is located at 10 to 20 wt.% Ni at the pressure of the inner core boundary. The fcc phase could crystallize depending on the nickel and silicon contents in the Earth's core, both of which are fcc stabilizer. (C) 2008 Elsevier B.V. All rights reserved.