The phase diagram of iron to 430 kbar
The phase diagram of iron to 430 kbar
复制标题
铁至 430 kbar 的相图
DOI：
--
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
R. Boehler
中科院分区：
文献类型：
--
作者：
R. Boehler
在430 kbar的内热式金刚石槽中测量了纯铁的e - γ转变和熔化曲线。样品是一根直径为0.02 mm的铁丝，用氧化铝作为压力介质，在夹层垫圈中连续加热。相变是由加热丝的电阻-温度曲线的不连续性决定的。通过将黑体辐射函数拟合到热线的发射光谱，用光学多通道分析仪（OMA）测量温度。在室温下使用红宝石刻度测量压力。根据Huang等（1986）关于α - e转变的新数据和目前关于e - γ转变的结果，得到α - e - γ三相点为116 kbar和810 K。e - γ转变的斜率为2.9 K/kbar。在500千巴时，铁的熔化温度比安德森（1986）计算的温度低1000 K。根据这些数据，我们可以预期在750 kbar和2500 K下会有一个e - γ - 1三相点。因此，在2兆巴的冲击波实验中发现的固体-固体转变可能是一种新的铁相的出现，这可能是地球内核的相。
The e - γ transition and the melting curve of pure iron have been measured in an internally heated diamond cell to 430 kbar. The sample, an iron wire with 0.02-mm diameter, was resistively heated in a sandwiched gasket arrangement, using alumina as the pressure medium. The phase transitions were determined by discontinuities in the resistance-temperature curves of the heated wire. Temperatures were measured with an optical multi-channel analyzer (OMA) by fitting a black-body radiation function to the emission spectrum of the hot wire. Pressures were measured at room temperature using the ruby scale. New data on the α - e transition by Huang et al. (1986) and the present result on the e - γ transition yield a α - e - γ triple point of 116 kbar and 810 K. The slope of the e - γ transition is 2.9 K/kbar. At 500 kbar the present melting temperatures of iron are about 1000 K lower than those calculated by Anderson (1986). From this data, one would expect a e - γ - 1 triple point at 750 kbar and 2500 K. The solid-solid transition found in shock wave experiments at 2 Mbar could therefore be the appearance of a new iron phase, which would be the phase of the inner core of the Earth.