Conventional and microwave-assisted sintering of ZnO-containing CAC-bonded alumina-based refractory castables

Autor(es)

Borges, O. H. ; Cardoso, A. L. F. ; Moreira, M. H. ; Klein-Gunnewiek, R. F. ; Pandolfelli, V. C.

• Tipo de documento: Artigo Científico
• Fonte: Journal of the European Ceramic Society; v. 43, n. 14, p. 9-pg., 2023-11-01.

Resumo

Recent studies have pointed out that ZnO can induce early spinel formation in alumina-based refractories, giving rise to gahnite (ZnAl2O4). Besides that, the high microwave absorption of zincite enables the likelihood of applying this sintering technique to compositions comprising this oxide. In this work, microwave and conventional sintering were applied to ZnO-containing alumina-based refractory castables. Microwave-processed samples displayed higher densification, enhanced mechanical properties at RT, a faster sintering schedule, and 70%-lower energy consumption compared to the conventionally produced counterparts, which could be attributed to the higher heating rates and enhanced ion diffusion induced by the electromagnetic-assisted sintering. Moreover, thermodynamic and experimental analyses indicated that the oxidation of SiC used as microwave susceptors induced zinc volatilization, resulting in small (similar to 40 mu m) pores in a densified refractory matrix. Although not necessarily detrimental to the castables' properties, this volatilization was reduced by controlling the atmosphere of the microwave cavity during sintering. (AU)

• Processo FAPESP: 21/00251-0 - Análise da secagem de concretos refratários via modelagem computacional e tomografia de nêutrons
• Beneficiário: Murilo Henrique Moreira
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 21/00114-2 - Desenvolvimento de concretos refratários espinelizados avançados eco-amigáveis em substituição aos materiais contendo cromita
• Beneficiário: Otávio Henrique Borges
• Modalidade de apoio: Bolsas no Brasil - Doutorado