Tecnologia em Metalurgia, Materiais e Mineração
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

Addition of hematite as a sintering aid in alumina: effect of concentration on physical, microstructural and mechanical properties

Pedro Henrique Poubel Mendonça da Silveira; Amal Elzubair Eltom; Jheison Lopes dos Santos; Geovana Carla Girondi Delaqua; Carlos Maurício Fontes Vieira; Paulo Roberto Rodrigues de Jesus; Marcelo Henrique Prado da Silva; Alaelson Vieira Gomes

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Hematite (Fe2 O3), or ferric oxide, is a ceramic oxide that, despite being recognized in the field of science and materials engineering, finds limited use as a sintering additive. Therefore, the purpose of this study was to explore the incorporation of hematite as a sintering additive in alumina (AIO3), employing conventional sintering at 1400 °C. Seven compositions were processed, with Fe2 O3 content varying from 0 to 8 wt.%. The samples underwent conventional ceramic processing steps (homogenization, drying, deagglomeration, sieving, and cold uniaxial pressing), followed by sintering at 1400 °C. The physical and mechanical properties of the produced samples were assessed through dilatometry, density measurement using the Archimedes’ method, scanning electron microscopy with energy-dispersive spectroscopy (SEM/ EDS), and flexural and compression tests. The results revealed that the addition of 4 and 6 wt.% of Fe2 O3 resulted in reduced shrinkage of the ceramics, leading to low densification, highly porous surfaces, and diminished flexural strength. On the other hand, lower additions (0.5, 1, and 2 wt.%) of Fe2 O3 improved the sintering of Al2 O3 , yielding samples with increased flexural and compressive strength, linear shrinkage, and densification.


Alumina; Hematite; Flexural resistance; Sintering


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