Melting Temperature of Iron Determined in an Internal-Resistance-Heated Diamond-Anvil Cell

Abstract

The Earth's core is mainly composed of iron. Since liquid outer core coexists with solid at the inner core boundary (ICB), the melting temperature of iron provides a key constraint on the temperature of the core. In this article, we will introduce our recent progress on the experimental approach to determine the melting temperature of iron at high-pressure by using internal-resistance-heated diamond-anvil cell. We determined the melting temperature of pure iron up to 290 GPa, for the first time above 200 GPa by static compression experiments. A small extrapolation of the present experimental results yields a melting point of 5,500±220 K at the ICB.