The Phase Diagram GdF3-LuF3

TL;DR

This study maps the phase diagram of gadolinium fluoride and lutetium fluoride, revealing their solubility limits, phase transformations, and reactions upon heating using calorimetry and X-ray diffraction techniques.

Contribution

It provides the first detailed phase diagram of GdF3-LuF3, including solubility limits and phase transformation data, using DSC and X-ray diffraction.

Findings

Unlimited mutual solubility in the orthorhombic phase.

Maximum Lu solubility in GdF3 high-temperature phase is about 20%.

Maximum Gd solubility in LuF3 is about 40%.

Abstract

The phase diagram gadolinium fluoride - lutetium fluoride was determined by differential scanning calorimetry (DSC) and X-ray powder diffraction analysis. Both pure components undergo a reversible first order transformation to a high temperature phase. The mutual solubility of both components is unlimited in the orthorhombic room temperature phase. The maximum solubility of Lu in the high temperature phase of GdF3 (tysonite type) is about 20% and the maximum solubility of Gd in LuF3 ($\alpha$-YF3 type) is about 40%. Intermediate compositions of the low temperature phase decompose upon heating in a peritectoid reaction to a mixture of both high temperature phases.