Thermophysical Property Measurements of Liquid and Supercooled Iridium by Containerless Methods

Thermophysical properties of equilibrium and supercooled liquid iridium were measured using noncontact diagnostic techniques in an electrostatic levitator. Over the 2300–3000K temperature range, the density can be expressed as ρ(T ) = 19.5 × 103 − 0.85(T − Tm) (kg·m−3) with Tm = 2719 K. The volume expansion coefficient is given by 4.4×10−5 K−1. In addition, the surface tension can be expressed as γ (T )=2.23×103−0.17(T −Tm)(10−3N·m−1) over the 2373–2833K span and the viscosity as η(T ) = 1.85 exp[3.0 × 104/(RT )](10−3Pa·s) over the same temperature range.