Influência do tamanho de grão e da quantidade de alumina na degradação hidrotermal de compósitos zircônia-alumina

Abstract

Advanced ceramic composites have been widely studied with the aim of developing materials that present increasingly improved properties. In the area of biomaterials, zirconia and alumina composites stand out due to the combination of their mechanical properties and biocompatibility. This work aimed to produce zirconia composites with the addition of submicrometric alumina particles, evaluating the influence of grain size and the amount of alumina added on the behavior against hydrothermal degradation, with a focus on their application in the dental area. For this purpose, zirconia and zirconia ceramic powders containing 5, 15, 20 and 50% by volume of alumina were processed, compacted and sintered. In order to obtain different grain sizes, the strategy adopted was to change the dwell sintering, as well as to use the two-steps sintering. The sintered composites were characterized by apparent density measurements, scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD) and 3D optical profilometry. To evaluate the stability to hydrothermal degradation, an accelerated aging test was performed in an autoclave, followed by characterization by Raman spectroscopy, XRD and 3D optical profilometry. The results indicated that the presence of alumina significantly influences the hydrothermal degradation of the composite, as well as the grain size.