[S-IT17] 地球型惑星内部での液体の特性とその役割

[SIT17-04] Density and thermal expansion of liquid and solid iron at 1 atm determined using high-temperature furnace

★Invited Papers

*寺崎 英紀¹、神谷 朝香²、近藤 忠² (1.岡山大学自然科学研究科地球科学専攻、2.大阪大学理学研究科宇宙地球科学専攻)

キーワード：密度、熱膨張率、鉄、液体

To estimate the structure and composition of a planetary core, the equation of state of iron alloys is an important information, along with planetary exploration data. The density and thermal expansion coefficient is one of the most fundamental characteristics to describe the equation of state. In this study, we precisely measured the densities of solid and liquid iron at high temperatures and ambient pressure using a high-temperature furnace with optical windows. The sample volume was determined from the optical image measured at each temperature. The density error of solid Fe was estimated to 0.11–0.7% in the temperature range of 295–1803 K with increments of 1–10 K. The two discontinuous density jumps were observed at 1162 and 1666 K which were derived from phase transitions (alpha/gamma/delta phases). The density decreased linearly with increasing temperature in each phase. For liquid, the density of liquid Fe was determined with uncertainty of 0.4–0.7% in the range of 1818–1998 K with temperature increments of 5 K. The obtained thermal expansion coefficient of liquid iron was 2.42(1) x 10^-4 K^-1.