Electrical Resistivity of Iron Phosphides at High-Pressure and High-Temperature Conditions With Implications for Lunar Core's Thermal Conductivity
Electrical Resistivity of Iron Phosphides at High-Pressure and High-Temperature Conditions With Implications for Lunar Core's Thermal Conductivity
复制标题
磷化铁在高压和高温条件下的电阻率对月核热导率的影响
DOI：
10.1029/2018jb017157
复制
发表时间：
2019
影响因子：
3.9
通讯作者：
Zhai Shuangmeng
中科院分区：
文献类型：
--
作者：
Yin Yuan;Zhai Kuan;Zhang Baohua;Zhai Shuangmeng
基于宇宙化学证据和元素分配实验，磷被认为存在于地球和月球的富铁核心中。在核心条件下，磷对铁的电和热输运性质具有与硅和硫类似的影响。然而，由磷引起的杂质散射的大小，铁磷化合物的温度依赖性，以及跨熔化的变化都没有得到深入的研究。我们使用四线法在1.3至3.2 GPa和高达1800 K的温度下测量了Fe 3 P、Fe 2 P和FeP的电阻率。我们还确定了FeP，Fe 2 P和Fe 3 P的熔化温度加热时电阻率的突然变化。实验结果表明，磷比硅能更有效地提高铁的电阻率。磷化铁的电阻率随压力的增加和磷含量的降低而降低。Fe-P合金的电阻率服从Matthiessen规则，该规则描述了电阻率与磷含量之间的正线性相关性。这一发现与以前在Fe-Si和Fe-C系统中观察到的原子有序无序相当。此外，液态Fe_2P和Fe_3P的电阻率与温度呈负线性相关。与纯铁不同，Fe 3 P的计算热导率在熔化后增加了33%。据推测，当有序铁轻元素化合物（例如，Fe 3C和Fe 3 P）存在于固体核中。
Based on cosmochemistry evidence and element partitioning experiments, phosphorus is thought to be present in the iron‐rich cores of Earth and Moon. Phosphorus has a similar effect as silicon and sulfur on the electrical and thermal transport properties of iron at core conditions. However, the magnitude of the impurity scattering caused by phosphorus, the temperature dependence of iron phosphorus compounds, and the change across melting all have not been intensively investigated. We measured the electrical resistivity of Fe3P, Fe2P, and FeP using a four‐wire method at 1.3 to 3.2 GPa and temperatures up to 1800 K. We also identify the melting temperatures of FeP, Fe2P, and Fe3P by sudden changes in resistivity upon heating. The present experimental results demonstrate that phosphorus can enhance the electrical resistivity of iron more effectively than silicon. The resistivity of iron phosphides decreases with increasing pressures and decreasing phosphorus content. The resistivity of Fe‐P alloys obeys the Matthiessen's rule, which describes the positive linear correlation between resistivity and phosphorus content. This finding is comparable to previously observed atomic order‐disorder in Fe‐Si and Fe‐C systems. Furthermore, the resistivity of liquid Fe2P and Fe3P shows a negative linear correlation with temperatures. Different from pure iron, the calculated thermal conductivity of Fe3P increases by 33% upon melting. It is speculated that the thermal conductivity of the lunar solid inner core may be much lower than that of the liquid outer core when ordered iron light element compounds (e.g., Fe3C and Fe3P) are present in the solid core.