Artigo 20 – Vol. 6 N. 3


THE THERMAL DECOMPOSITION OF HYDRATED ZrOCl 2 REVISITED

Autores
Gerard J. Puts, Salmon J. Lubbe,Philip L. Crouse
Recebido em
 10 de Maio de 2017
Aceito em
 10 de Agosto de 2017
Publicado em
 30 de Setembro de 2017
DOI
 10.18362/bjta.v6.i3.20
Páginas
Keywords
Zirconyl chloride, zirconium oxychloride, thermal decomposition, zirconia

 

Resumo

New data, generated using TGA-FTIR, TGA-DTA, HR-TGA, and in-situ XRD, as well as morphological investigation of the residues with HR-SEM, show that the morphology of the product ZrO 2 is highly dependent on the hydration state and Cl-to- Zr molar ratio of the starting material, as well as the heating rate. At lower heating rates, the ZrO 2 product forms spherules, but maintain the bulk morphology of the parent ZrOCl 2 crystal, while at heating rates higher than 10°C∙min -1 the bulk morphology is progressively lost, being completely absent at a heating rate of 50°C∙min -1 . The gaseous decomposition products consist of H 2 O and HCl, regardless of the nature of the decomposition atmosphere, contrary to the claimed in older literature that Cl 2 instead of HCl may be released under oxidising atmosphere. An updated model for the formation of ZrO 2 from ZrOCl 2 is proposed.
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