Density of Liquid Niobium and Tungsten and the Estimation of Critical Point Data

Density as a function of temperature was measured for the liquid transition metals niobium and tungsten by means of ohmic pulse-heating. The generated data are extensively compared to the existing literature data, and the uncertainty is critically assessed according to the guide to the expression of uncertainty in measurement (GUM). Starting from the obtained liquid-phase density regression, the phase diagram, and the critical point, i.e. , critical temperature T c and critical density ρ c of niobium and tungsten are estimated. The so-obtained critical point for these two high-melting metals is compared to the data available in the existing literature.