Effect of Alumina Proportion on the Microstructure and Technical and Mechanical Characteristics of Zirconia-Based Porous Ceramics

Abstract

The current study investigates the process of preparing and analysing porous-structured ceramics made from zirconium, aluminium, and magnesium ceramic oxides. The starch consolidation casting (SCC) technique, with different types of starches (potato and tapioca), was used for this purpose. Our objective was to methodically examine the impact of different processing factors, such as the temperature at which pre-sintering and sintering occur, and the proportions of ceramic powders, on the microstructure, mechanical characteristics, and porosity of the resultant composites. Pre-sintering effectively reduced the rate of shrinkage during the final sintering stage; this resulted in more controlled and predictable shrinkage, leading to better dimensional stability and reduced risk of defects in the final product. A higher alumina content was associated with an increase in apparent porosity and a reduction in volume shrinkage and apparent densities. The mercury intrusion porosimetry (MIP) findings concluded that the prepared porous ceramics have a multi-modal pore structure. The highest calculated compressive strength was 76.89 MPa for a sample with a porous structure, which was manufactured using 20 wt.% tapioca starch and 30 wt.% alumina content. The main advantage of alumina is its ability to improve compressive strength by refining the grain structure and serving as a barrier against fracture development.