Monoclinic - Tetragonal Zirconia quantification of commercial nanopowder mixtures by XRD and DTA

MATÍAS GAUNA; MARÍA SUSANA CONCONI; SOFÍA GÓMEZ; GUSTAVO SUÁREZ; ESTEBAN AGLIETTI; NICOLÁS RENDTORFF

CERAMICS-SILIKáTY

INST CHEMICAL TECHNOLOGY

Lugar: Praga; Año: 2015

0862-5468

The phase quantification in ceramic nanopowders presents technological interest forstudying and design purposes. Especially in zirconia ceramics where the mechanicaland transport properties are strongly affected by the crystalline composition. In thiswork we present the comparison XRD based methods and differential thermal analysismethods for phase characterization and specially quantification.A complete series of commercial nanopowders mixtures (D50 ≈ 0.1 m) of monocliniczirconia (m) and partially stabilized zirconia (t: 3% yttrium oxide) was studied.X ray diffraction (XRD) was performed and the relation m:t was quantified by the socalled Garvie-Nicholson (G-N), Toraya and Rietveld method.A complete reversible DTA analysis was carried out to the same mixtures. Both m-tand t-m martensitic thermal transformations were observed and pondered for the mZrO2containing samples. The graphical integration was performed and employed forthe construction of a calibration curve in the studied composition range.The results were compared, the Toraya method presented equivalent results incomparison with the Rietveld method. The G-N method presented appreciabledifferences (≈10%).The direct proportionally of the pure m-ZrO2 peak area resulted in important errors butif a simple calibration curve is constructed, the DTA method presents accuratequantification with results comparable to the best XRD based quantification.