Deriving Thermophysical Properties of Undercooled Liquid Zr from Radiative Cooling Curves Measured by Containerless Electrostatic Levitation

Abstract

An analytical way of deriving constant pressure specific heat cP(T) and hemispherical total emissivity εT(T) of materials in the undercooled liquid state is presented. A t(T) function in a time-temperature profile was analytically determined from the radiative cooling curves of Zr measured by electrostatic levitation (ESL) in which a bulk sample was electrostatically charged and levitated then melted by laser irradiation in high vacuum. The cooling behavior of liquid Zr was found to be well described by an inverse bi-quadratic polynomial of t(T). The cP(T)/εT(T) ratio was then estimated, and εT(T) and cP(T) were calculated; they were found to be consistent with the reference data in the literature. This implies that the rationale behind the analytical approach taken in this study is reasonable and can be applied to estimating the cP(T)/εT(T) ratio, thus further facilitating derivation of εT(T) and cP(T) of various materials.