Structural features of phosphate and sulfate modified zirconia prepared by sol-gel route
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Data
2004-10-01
Autores
Kawaguti, C. A.
Chiavacci, L. A.
Pulcinelli, Sandra Helena [UNESP]
Santilli, Celso Valentim [UNESP]
Briois, V
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Editor
Springer
Resumo
This paper describes the effect of sulfate, phosphate and nitrate complexing ligands on the structural features of amorphous xerogels and on the crystallization of metastable zirconia phases during the xerogel-ceramic conversion. Powdered samples were prepared by a sol-gel route using zirconyl chloride precursors chemically modified by complexing ligands. The structural evolution of ZrO2 phases as function of firing temperature was analyzed by XRPD, EXAFS and P-13 NMR/MAS. The experimental results show the formation of metastable t-ZrO2 during the low firing temperature of xerogels modified by sulfate or phosphate groups. The martensitic tetragonal-monoclinic transformation occurs during desorption of sulfate groups. The largest temperature interval of stability of metastable tetragonal zirconia was observed for phosphate-modified xerogels.
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Palavras-chave
sol-gel process, zirconia tetragonal phase
Como citar
Journal of Sol-gel Science and Technology. Dordrecht: Springer, v. 32, n. 1-3, p. 91-97, 2004.