Relation between mechanical and textural properties of dense materials of tetragonal and cubic zirconia

SOFIA GOMEZ; SUAREZ GUSTAVO; NICOLAS M. RENDTORFF; ESTEBAN F. AGLIETTI

SCIENCE OF SINTERING

INT INST SCIENCE SINTERING (I I S S)

Año: 2015

0350-820X

In the current paper we present a study of the sinterability of two zirconia (ZrO2) nanopowders (D50 ≤100nm). A couple of stabilized zirconia powders with different content of yttrium oxide (Y2O3): 3 and 8 % tetragonal and cubic zirconia respectively were studied. The powders were previously characterized by evaluation of the grain size and morphology by scanning electron microscopy (SEM). The crystalline composition of the powders was evaluated by X-ray diffraction (XRD) and the structure was also examined employing the Rietveld refinement method. Zirconia nanopowders were uniaxial pressed in samples and sintered with identical heating and cooling rate and dwell time, 5ºC/min and 180 minutes respectively between 900-1500ºC. After sintering, the samples were characterized in terms of their density and porosity, using Archimedes technique. Their grain size was evaluated using scanning electron microscope (SEM). Vickers hardness and fracture toughness (KIC) were measured by the indentation method. Finally the correlation between the processing variable and the properties were established.The results showed that pores are almost eliminated at sintering temperatures more than 1400ºC and grain size is larger due to the agglomerates that are formed as a result of grain growth. Vickers hardness evaluated in 1400ºC sintering temperature is greater than that obtained at 1500ºC due to grain growth produced at this temperature.In addition, we show a correlation of Vickers hardness with the porosity, obtained by evaluating empirical and theoretical models.