Electrical Resistivity of the Fe-Si-S Ternary System: Implications for Timing of Thermal Convection Shutdown in the Lunar Core

The electrical resistivity of Fe-14wt.%Si-3wt.%S was measured using a four-wire resistance technique in both solid and molten states at pressures up to 5 GPa and thermal conductivity was calculated via the Wiedemann-Franz Law from the electrical measurements. The results were used to estimate the adiabatic conductive heat flux of a molten Fe-14wt.%Si-3wt.%S lunar core and compared to a Fe-2-17wt.%Si lunar core from a previous study, which showed that thermal convection of either core composition shuts down within the duration of a high intensity paleomagnetic field.采用四线制电阻测量技术，在最高5吉帕斯卡（GPa）的压力条件下，于固态与熔融态范围内测量了Fe-14wt.%Si-3wt.%S合金的电阻率；并基于电阻率测试数据，通过维德曼-弗兰兹定律（Wiedemann-Franz Law）计算得到该合金的热导率。利用上述实验结果，估算了Fe-14wt.%Si-3wt.%S熔融态月球核的绝热传导热通量，并将其与前人研究中Fe-2-17wt.%Si月球核的相关结果进行对比。对比结果表明，两种成分的月球核的热对流均会在高强度古磁场的存续周期内终止。