Structural and mechanical characterization of mullite and aluminium titanate reinforced yttria stabilized zirconia ceramic composites

Abstract

3 mole % yttria stabilized zirconia (YSZ) ceramic and 20 wt. % mullite (M), and 20 wt. % aluminium titanate (AT) reinforced YSZ ceramic composites were produced using a conventional ceramic production process. After a combined method of wet ball milling and dry pressing, these samples were sintered at 1500 degrees C and 1600 degrees C for 1hr and 5hrs, respectively. Physical properties, microstructural and phase characterizations of the sintered samples were analyzed using Archimedes method, a scanning electron microscope with energy dispersive spectroscopy and X-ray diffraction technique, respectively. Thereafter, micro Vickers and three-point bending tests were performed. The density, relative density and firing shrinkage of the sintered samples increased with addition of M and AT and the increased sintering temperature at each time. However, both porosity and loss of water properties determined were inversely proportional to M and AT addition and sintering temperature and time increase. An increase in M and AT content influenced the grain morphology as is presented in the microstructures of the composites produced thus bringing about a rise in grain size, as well as homogeneity and density in YSZ samples. Promising results were observed with the Vickers and bending strength in the mullite reinforced YSZ samples sintered at 1600 degrees C for 5hrs due to mullite addition, which provides excellent mechanical features to the YSZ ceramic composites.