Manufacturing and properties evaluation of Al₂O₃/ZrO₂ granules derived from sodium alginate gelation

Spherical millimeter-sized ceramics with porous and dense microstructure are materials of interest in approaches related to catalytic supports and milling media. The reliability of these operations depends on key characteristics of these materials, including high sphericity to ensure efficient process designing, ease of handling, facile separation and/or recyclability, abrasion resistance, and uniform packing. This is accompanied by the structural stability and microstructure tailoring to secure its functionality. The Al₂O₃/ZrO₂ system has been applied in powdered form for catalytic support applications, and in both porous and dense ceramics for structural applications, highlighting the performance and functionality of the Al₂O₃/ZrO₂ system in these approaches. Based on this analysis, the present study explores the optimized preparation of spherical millimeter-sized Al₂O₃/ZrO₂ granules along with the assessment of their microstructural, mechanical, and pore-related outcomes as a function of the heat treatment conditions. Optimized Al₂O₃/ZrO₂ granules with high sphericity, processed through sodium alginate gelation at 900 °C and 1100 °C displayed a hierarchical macro/mesoporosity which can provide potential functionality for catalytic supports-related applications. In comparison Al₂O₃/ZrO₂ granules similarly processed at a sintering temperature of 1600 °C exhibited a tailored mechanical strength and high relative density ensured by a refined microstructure, as well as a high sphericity which are features preferred for milling media applications.