Microstructural modifications of polyethylene glycol powder binder in the processing of sintered alpha alumina under different conditions of preparation

In this study, amounts of polyethylene glycol (PEG) plasticizer which used in the forming and sintering α-alumina ceramics of the sample are optimized. PEG as a conventional binder is used for the preparation of alumina-based materials. The main aim of this work was to investigate the effect of different contents of PEG and sintering conditions on the critical quality of produced alumina including microstructure, porosity, compressibility, and mechanical properties. Also, the influence of compression pressure (from 3500 to 5000 bar) on the green density of the produced alumina pellets was evaluated while the binder contents are varied from 1 to 5 wt%. The analysis results showed that the addition of PEG to the alumina powder enhances the green density of the produced disks until a maximum value. Over the maximum point, the density did not further change with increasing PEG content. This high green density leads to a high sintered density of the alumina disks. The results show that the formulation containing more than 4 wt% of PEG causes both lower sintered and green density. The fabricated alumina pellets were then compared to those without additives in terms of mechanical strength, and it was indicated that the density of fabricated pellets enhanced by rising the compaction pressure greater than 3500 bar. Keywords: α-Alumina, Mechanical properties, Modification, Sinterability, Binders, Green density, PE