A thermogravimetric study of the fluorination of zirconium and hafnium oxides with fluorine gas

The fluorination of ZrO2 and HfO2 and the understanding of the fundamental chemistry of formation of ZrF4 and HfF4 in a fluorine atmosphere were investigated using a thermobalance. The fluorination of these species was performed to understand the chemical behavior of the tetrafluoride species of these metals. Thermogravimetrical analysis indicated that the formation of ZrF4/HfF4 is via the oxyfluorides. X-ray powder diffraction was used to confirm the results.

Thermogravimetric investigation of the fluorination of ZrO2 and HfO2 using fluorine gas.Figure optionsDownload as PowerPoint slideHighlights
► ZrO2 and HfO2 were fluorinated using a thermobalance in a F2 atmosphere.
► Dynamic TG runs showed the possible formation of stable intermediates.
► Isothermal runs confirmed that the intermediate formed is temperature dependent.
► XRD confirmed in some cases that the intermediates are oxyfluorides.
► XRD confirmed the formation of ZrF4 and HfF4 at 525 and 580 °C, respectively.