In-Situ Phase Equilibria up to 3000 ˚C and Beyond

Experimental equilibrium phase diagrams have proved to be difficult to produce for materials above 1500 ˚C. Here we show how the experimental HfO₂-Ta₂O₅-TiO₂ phase diagram was elucidated using laser-heated levitated samples up to 3000 ˚C. The experiments performed are a combination of in-situ high temperature X-ray diffraction for phase identification and the study of phase transformations. Here we will examine the Hf₆Ta₂O₁₇ peritectic reaction. In addition, we will show how recoalescence experiments are performed on levitated samples to determine melting points. Steps will then be provided on how this system is being adjusted to reach temperatures of up to 4500 ˚C and how this work will be extended to carbide, nitride and boride high temperature phase equilibria.